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  • 1.
    Arslan, Engin
    et al.
    Bilkent University, Turkey .
    Cakmakyapan, Semih
    Bilkent University, Turkey .
    Kazar, Ozgur
    Bilkent University, Turkey .
    Butun, Serkan
    Bilkent University, Turkey .
    Bora Lisesivdin, Sefer
    Gazi University, Turkey .
    Cinel, Neval A.
    Bilkent University, Turkey .
    Ertas, Gulay
    Bilkent University, Turkey .
    Ardali, Sukru
    Anadolu University, Turkey .
    Tiras, Engin
    Anadolu University, Turkey .
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ozbay, Ekmel
    Bilkent University, Turkey .
    SiC Substrate Effects on Electron Transport in the Epitaxial Graphene Layer2014In: ELECTRONIC MATERIALS LETTERS, ISSN 1738-8090, Vol. 10, no 2, p. 387-391Article in journal (Refereed)
    Abstract [en]

    Hall effect measurements on epitaxial graphene (EG) on SiC substrate have been carried out as a function of temperature. The mobility and concentration of electrons within the two-dimensional electron gas (2DEG) at the EG layers and within the underlying SiC substrate are readily separated and characterized by the simple parallel conduction extraction method (SPCEM). Two electron carriers are identified in the EG/SiC sample: one high-mobility carrier (3493 cm(2)/Vs at 300 K) and one low-mobility carrier (1115 cm(2)/Vs at 300 K). The high mobility carrier can be assigned to the graphene layers. The second carrier has been assigned to the SiC substrate.

  • 2.
    Bergman, Peder
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Booker, Ian Don
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lilja, Louise
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Radial Variation of Measured Carrier Lifetimes in Epitaxial Layers Grown with Wafer Rotation2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 289-292Conference paper (Refereed)
    Abstract [en]

    In this report we present homoepitaxial growth of 4H-SiC on the Si-face of nominally on-axis substrates with diameter up to 100 mm in a hot-wall chemical vapor deposition reactor. A comparatively low carrier lifetime has been observed in these layers. Also, local variations in carrier lifetime are different from standard off-cut epilayers. The properties of layers were studied with more focus on charge carrier lifetime and its correlation with starting growth conditions, inhomogeneous surface morphology and different growth mechanisms.

  • 3.
    Bergman, Peder
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Godignon, P.
    Brosselard, P.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Improved SiC Epitaxial Material for Bipolar Applications2008In: Proc. of MRS Spring Meeting 2008, 2008, p. D05-Conference paper (Refereed)
    Abstract [en]

    Epitaxial growth on Si-face nominally on-axis 4H-SiC substrates has been performed using horizontal Hot-wall chemical vapor deposition system. The formation of 3C inclusions is one of the main problem with growth on on-axis Si-face substrates. In situ surface preparation, starting growth parameters and growth temperature are found to play a vital role in the epilayer polytype stability. High quality epilayers with 100% 4H-SiC were obtained on full 2″ substrates. Different optical and structural techniques were used to characterize the material and to understand the growth mechanisms. It was found that the replication of the basal plane dislocation from the substrate into the epilayer can be eliminated through growth on on-axis substrates. Also, no other kind of structural defects were found in the grown epilayers. These layers have also been processed for simple PiN structures to observe any bipolar degradation. More than 70% of the diodes showed no forward voltage drift during 30 min operation at 100 A/cm2.

  • 4.
    Booker, Ian D.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Farkas, Ildiko
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Chloride-based SiC growth on a-axis 4H-€“SiC substrates2016In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 480, p. 23-25Article in journal (Refereed)
    Abstract [en]

    Abstract SiC has, during the last few years, become increasingly important as a power-device material for high voltage applications. The thick, low-doped voltage-supporting epitaxial layer is normally grown by CVD on 4° off-cut 4H–SiC substrates at a growth rate of 5 – 10 ÎŒ m / h using silane (SiH4) and propane (C3H8) or ethylene (C2H4) as precursors. The concentrations of epitaxial defects and dislocations depend to a large extent on the underlying substrate but can also be influenced by the actual epitaxial growth process. Here we will present a study on the properties of the epitaxial layers grown by a Cl-based technique on an a-axis (90° off-cut from c-direction) 4H–SiC substrate.

  • 5.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Abdalla, Hassan
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Karhu, Robin
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Lilja, Louise
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sveinbjörnsson, Einar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Science Institute, University of Iceland, Reykjavik, Iceland.
    Oxidation-induced deep levels in n- and p-type 4H- and 6H-SiC and their influence on carrier lifetime2016In: Physical Review Applied, ISSN 2331-7019, Vol. 6, no 1, p. 1-15, article id 014010Article in journal (Refereed)
    Abstract [en]

    We present a complete analysis of the electron- and hole-capture and -emission processes of the deep levels ON1, ON2a, and ON2b in 4H-SiC and their 6H-SiC counterparts OS1a and OS1b through OS3a and OS3b, which are produced by lifetime enhancement oxidation or implantation and annealing techniques. The modeling is based on a simultaneous numerical fitting of multiple high-resolution capacitance deep-level transient spectroscopy spectra measured with different filling-pulse lengths in n- and p-type material. All defects are found to be double-donor-type positive-U two-level defects with very small hole-capture cross sections, making them recombination centers of low efficiency, in accordance with minority-carrier-lifetime measurements. Their behavior as trapping and weak recombination centers, their large concentrations resulting from the lifetime enhancement oxidations, and their high thermal stability, however, make it advisable to minimize their presence in active regions of devices, for example, the base layer of bipolar junction transistors.

  • 6.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Abdalla, Hassan
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, The Institute of Technology.
    Lilja, L.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sveinbjörnsson, Einar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Oxidation induced ON1, ON2a/b defects in 4H-SiC characterized by DLTS2014In: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2, Trans Tech Publications , 2014, Vol. 778-780, p. 281-284Conference paper (Refereed)
    Abstract [en]

    The deep levels ON1 and ON2a/b introduced by oxidation into 4H-SiC are characterized via standard DLTS and via filling pulse dependent DLTS measurements. Separation of the closely spaced ON2a/b defect is achieved by using a higher resolution correlation function (Gaver-Stehfest 4) and apparent energy level, apparent electron capture cross section and filling pulse measurement derived capture cross sections are given.

  • 7.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hallén,, Anders
    Royal Institute of Technology, Sweden.
    Sveinbjörnsson, Einar Ö.
    University of Iceland, Reykjavik, Iceland.
    Kordina, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Comparison of Post-Growth Carrier Lifetime Improvement Methods for 4H-SiC Epilayers2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 285-288Conference paper (Refereed)
    Abstract [en]

    We compare two methods for post-growth improvement of bulk carrier lifetime in 4H-SiC: dry oxidations and implantations with either C-12 or N-14, followed by high temperature anneals in Ar atmosphere. Application of these techniques to samples cut from the same wafer/epilayer yields 2- to 11-fold lifetime increases, with the implantation/annealing technive shown to give greater rnaximum lifetimes. The maximum lifetimes reached are similar to 5 mu s after C-12 implantation at 600 degrees C and annealing in Ar for 180 minutes at 1500 degrees C. At higher annealing temperatures the lifetimes decreases, a result which differs from reports in the literature.

  • 8.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    High-Resolution Time-Resolved Carrier Lifetime and Photoluminescence Mapping of 4H-SiC Epilayers2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 293-296Conference paper (Refereed)
    Abstract [en]

    We present a comparison between time-resolved carrier lifetime mappings of several samples and integrated near band edge intensity photoluminescence mappings using a pulsed laser. High-injection conditions and as-grown material are used, which generally allow for the assumption of a single exponential decay. The photoluminescence intensity under these circumstances is proportional to the carrier lifetime and the mappings can be used to detect lifetime-influencing defects in epilayers and give an estimate of the carrier lifetime variation over the wafer. Several examples for the defect detection capability of the system are given.

  • 9.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sveinbjörnsson, Einar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Science Institute, University of Iceland, Reykjavik, Iceland.
    Electron and hole capture cross sections of deep levels accessible by DLTS and MCTS in p-type 4H-SiCManuscript (preprint) (Other academic)
    Abstract [en]

    The effective electron (σn(T)) and hole (σn(T)) capture cross sections of the electrically active deep levels HK0, HK2, LB1 and EM1 found in as-grown, high temperature annealed and oxidized p-type 4H-SiC were measured by deep level transient spectroscopy (DLTS), minority carrier transient spectroscopy (MCTS) and optical-electrical MCTS and DLTS (OE-MCTS and EO-DLTS) in an effort to determine the potential recombination centers in p-type material. Additionally, we also find the D-center, and the deep levels EH6/7, ON1 and ON2 in our samples, while the levels HK1, HK3 and HK4, reported in literature, are always below the detection limit. We further compare deep level concentrations and the timeresolved photoluminescence (TRPL) measured low injection (τLI) in samples annealed at up to 1920 °C. None of the detected deep levels possess σp(T):σn(T) ratios which could enable them to act as efficient recombination centers in the annealed epilayers, where τLI ranges from 1.2·10-6 s to less than 100·10-9 s. However, a clear anti-correlation between τLI and the EH6/7 concentration is found, which is linked to the main lifetime limiting center in n-type material, Z1/2, via their common origin, the carbon vacancy. Due to their large σp(T):σn(T) ratio, the Z1/2 deep levels are not detected by frontside illumination MCTS in p-type material. We thus conclude that the main lifetime limiting deep level(s) in p-type 4HSiC appear to be located in the upper half of the bandgap and are most likely either Z1/2, or other deep levels of intrinsic or partially intrinsic origin with a similar σp(T):σn(T) ratio.

  • 10.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Stenberg, Pontus
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sveinbjörnsson, Einar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Science Institute, University of Iceland, Reykjavik, Iceland.
    Carrier lifetime in p- and n-type 4H-SiCManuscript (preprint) (Other academic)
    Abstract [en]

    Temperature-dependent time-resolved photoluminescence measurements made in the temperature range from 77 K to 1000 K on free-standing as grown n-type 4H-SiC and p-type 4H-SiC epilayers, which are either as-grown or annealed at 1000 °C, 1400 °C or 1700 °C, are analyzed. The development of the instantaneous carrier lifetime over temperature, calculated from the decay curves of all n- and p-type samples, is found to be identical in the entire temperature range. With increasing annealing temperature only the magnitude of the lifetime in p-type 4H-SiC decreases while the trend remains identical to that in the as-grown n-type sample. Annealing thus only increases the density of the main recombination center which appears to control lifetime in as-grown n- and p-type material. The results implies that the lifetime in all samples may be governed by the same intrinsic defect, which we suggest to be Z1/2.

  • 11.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Stenberg, Pontus
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sveinbjörnsson, Einar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Science Institute, University of Iceland, Reykjavik, Iceland.
    Donor and double donor transitions of the carbon vacancy related EH6/7 deep level in 4H-SiC2016In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, no 23, article id 235703Article in journal (Refereed)
    Abstract [en]

    Using medium- and high-resolution multi-spectra fitting of deep level transient spectroscopy (DLTS), minority carrier transient spectroscopy (MCTS), optical O-DLTS and optical-electrical (OE)-MCTS measurements, we show that the EH6∕7 deep level in 4H-SiC is composed of two strongly overlapping, two electron emission processes with thermal activation energies of 1.49 eV and 1.58 eV for EH6 and 1.48 eV and 1.66 eV for EH7. The electron emission peaks of EH7 completely overlap while the emission peaks of EH6 occur offset at slightly different temperatures in the spectra. OE-MCTS measurements of the hole capture cross section σp 0(T) in p-type samples reveal a trap-Auger process, whereby hole capture into the defect occupied by two electrons leads to a recombination event and the ejection of the second electron into the conduction band. Values of the hole and electron capture cross sections σn(T) and σp(T) differ strongly due to the donor like nature of the deep levels and while all σn(T) have a negative temperature dependence, the σp(T) appear to be temperature independent. Average values at the DLTS measurement temperature (∼600 K) are σn 2+(T) ≈ 1 × 10−14 cm2, σn +(T) ≈ 1 × 10−14 cm2, and σp 0(T) ≈ 9 × 10−18 cm2 for EH6 and σn 2+(T) ≈ 2 × 10−14 cm2, σn +(T) ≈ 2 × 10−14 cm2, σp 0(T) ≈ 1 × 10−20 cm2 for EH7. Since EH7 has already been identified as a donor transition of the carbon vacancy, we propose that the EH6∕7 center in total represents the overlapping first and second donor transitions of the carbon vacancy defects on both inequivalent lattice sites.

  • 12.
    Booker, Ian Don
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lilja, Louise
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Beyer, Franziska
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Karhu, Robin
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, J. Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Danielsson, Örjan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kordina, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sveinbjörnsson, Einar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Carrier Lifetime Controlling Defects Z(1/2) and RB1 in Standard and Chlorinated Chemistry Grown 4H-SiC2014In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, no 8, p. 4104-4110Article in journal (Refereed)
    Abstract [en]

    4H-SiC epilayers grown by standard and chlorinated chemistry were analyzed for their minority carrier lifetime and deep level recombination centers using time-resolved photoluminescence (TRPL) and standard deep level transient spectroscopy (DLTS). Next to the well-known Z(1/2) deep level a second effective lifetime killer, RB1 (activation energy 1.05 eV, electron capture cross section 2 x 10(-16) cm(2), suggested hole capture cross section (5 +/- 2) x 10(-15) cm(2)), is detected in chloride chemistry grown epilayers. Junction-DLTS and bulk recombination simulations are used to confirm the lifetime killing properties of this level. The measured RB1 concentration appears to be a function of the iron-related Fe1 level concentration, which is unintentionally introduced via the corrosion of reactor steel parts by the chlorinated chemistry. Reactor design and the growth zone temperature profile are thought to enable the formation of RB1 in the presence of iron contamination under conditions otherwise optimal for growth of material with very low Z(1/2) concentrations. The RB1 defect is either an intrinsic defect similar to RD1/2 or EH5 or a complex involving iron. Control of these corrosion issues allows the growth of material at a high growth rate and with high minority carrier lifetime based on Z(1/2) as the only bulk recombination center.

  • 13.
    Brosselard, P
    et al.
    Centro Nacional de Microelectrónica, CNM-CSIC, Campus UAB, 08193 Bellaterra, Barcelona, Spain .
    Berthou, M
    Centro Nacional de Microelectrónica, CNM-CSIC, Campus UAB, 08193 Bellaterra, Barcelona, Spain .
    Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jorda, X
    Centro Nacional de Microelectrónica, CNM-CSIC, Campus UAB, 08193 Bellaterra, Barcelona, Spain .
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Montserrat, J
    Centro Nacional de Microelectrónica, CNM-CSIC, Campus UAB, 08193 Bellaterra, Barcelona, Spain .
    Godignon, P
    Centro Nacional de Microelectrónica, CNM-CSIC, Campus UAB, 08193 Bellaterra, Barcelona, Spain .
    Millan, J
    Centro Nacional de Microelectrónica, CNM-CSIC, Campus UAB, 08193 Bellaterra, Barcelona, Spain .
    Comparison between 3.3kV 4H-SiC schottky and bipolar diodes2008In: IET Seminar Digest, Volume 2008, Issue 2, 2008, 2008, p. 87-91Conference paper (Refereed)
    Abstract [en]

    Silicon Carbide Schottky and bipolar diodes have been fabricated with a breakdown voltage of 3.3kV. Diodes have been packaged and measured up to 300°C. The Schottky diode shows an increase of voltage drop with temperature and a reverse recovery charge independent from temperature. The PiN diode reverse recovery charge is ×20 at 300°C compared to that of the Schottky diode. 55% of the stressed bipolar diodes at 20A show a very small forward voltage drift. Theswitching losses of these stressed diodes are reduced by 20%. Substrate quality enhancement makes large SiC component fabrication possible (25mm 2 Schottky diodes) and bipolar components show very small tension drift with temperature.

  • 14. Brosselard, P.
    et al.
    Camara, N.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Jordà, X.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Montserrat, J.
    Millán, J.
    3.3 kV-10A 4H-SiC PiN diodes2009In: Materials Science Forum, Vols. 600-603, Trans Tech Publ. , 2009, p. 991-994Conference paper (Refereed)
    Abstract [en]

    An innovative process has been developed by Linköping University to prepare the 4HSiC substrate surface before epitaxial growth. The processed PiN diodes have been characterized in forward and reverse mode at different temperature. The larger diodes (2.56 mm2) have a very low leakage current around 20 nA @ 500V for temperatures up to 300°C. A performant yield (68%) was obtained on these larger diodes have a breakdown voltage superior to 500V. Electroluminescence characteristics have been done on these devices and they show that there is no generation of Stacking Faults during the bipolar conduction.

  • 15.
    Brosselard, P
    et al.
    Centre Nacl Microelect IMB CNM CSIC.
    Perez-Tomas, A
    Centre Nacl Microelect IMB CNM CSIC.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Camara, N
    Centre Nacl Microelect IMB CNM CSIC.
    Jorda, X
    Centre Nacl Microelect IMB CNM CSIC.
    Vellvehi, M
    Centre Nacl Microelect IMB CNM CSIC.
    Godignon, P
    Centre Nacl Microelect IMB CNM CSIC.
    Millan, J
    Centre Nacl Microelect IMB CNM CSIC.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Low loss, large area 4.5 kV 4H-SiC PIN diodes with reduced forward voltage drift2009In: SEMICONDUCTOR SCIENCE AND TECHNOLOGY, ISSN 0268-1242, Vol. 24, no 9, p. 095004-Article in journal (Refereed)
    Abstract [en]

    4H-SiC PIN diodes have been fabricated on a Norstel P+/N/N+ substrate with a combination of Mesa and JTE as edge termination. A breakdown voltage of 4.5 kV has been measured at 1 mu A for devices with an active area of 2.6 mm(2). The differential on-resistance at 15 A (600 A cm(-2)) was of only 1.7 m Omega cm(2) (25 degrees C) and 1.9 m Omega cm(2) at 300 degrees C. The reduced recovery charge was of 300 nC for a switched current of 15 A (500 V) at 300 degrees C. 20% of the diodes showed no degradation at all after 60 h of dc stress (25-225 degrees C). Other 30% of the diodes exhibit a reduced voltage shift below 1 V. For those diodes, the leakage current remains unaffected after the dc stress. Electroluminescence investigations reveal a very low density of stacking faults after the dc stress. The manufacturing yield evidences the efficiency of the substrate surface preparation and our technological process.

  • 16. Brosselard, P.
    et al.
    Tomas, A.P.
    Camara, N.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Jorda, X.
    Vellvehi, M.
    Godignon, P.
    Millan, J.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    The effect of the temperature on the bipolar degradation of 3.3 kV 4H-SiC PiN diodes2008In: 20th International Symposium on Power Semiconductor Devices ICs,2008, Proceedings of the 20th International Symposium on Power Semiconductor Devices & ICs: Institute of Electrical and Electronics Engineers ( IEEE ) , 2008, p. 237-Conference paper (Refereed)
  • 17.
    Christle, David J.
    et al.
    University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA.
    Falk, Abram L.
    University of Chicago, IL 60637 USA.
    Andrich, Paolo
    University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA.
    Klimov, Paul V.
    University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Tien Son, Nguyen
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ohshima, Takeshi
    Japan Atom Energy Agency, Japan.
    Awschalom, David D.
    University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA.
    Isolated electron spins in silicon carbide with millisecond coherence times2015In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 14, no 2, p. 160-163Article in journal (Refereed)
    Abstract [en]

    The elimination of defects from SiC has facilitated its move to the forefront of the optoelectronics and power-electronics industries(1). Nonetheless, because certain SiC defects have electronic states with sharp optical and spin transitions, they are increasingly recognized as a platform for quantum information and nanoscale sensing(2-16). Here, we show that individual electron spins in high-purity monocrystalline 4H-SiC can be isolated and coherently controlled. Bound to neutral divacancy defects(2,3), these states exhibit exceptionally long ensemble Hahn-echo spin coherence times, exceeding 1 ms. Coherent control of single spins in a material amenable to advanced growth and microfabrication techniques is an exciting route towards wafer-scale quantum technologies.

  • 18.
    Ciechonski, Rafal
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Structural instabilities in growth of SiC crystals2005In: Journal of Crystal Growth, ISSN 0022-0248, Vol. 275, no 1-2, p. e461-e466Article in journal (Refereed)
    Abstract [en]

    Misoriented grains, which may occur on the growth front of 6H–SiC boules have been studied in relation to their appearance during sublimation growth. The effect was obtained by applying growth conditions at which the source powder was gradually approaching graphitisation and the vapour becoming C-rich. The high off-orientation of the grains is demonstrated through etching in molten KOH and transmission light optical microscopy. Micropipes propagating in the single crystal area and facing the misoriented grain have been studied, and it is shown that they may either be terminated at the grain or their propagation is altered to be parallel with the grain boundary. It has been found that the polytype of the grains may switch from 6H to 4H, which is explained by the change of the Si/C ratio in the vapour.

  • 19.
    Civrac, Gabriel
    et al.
    University of Lyon, France .
    Laariedh, Farah
    University of Lyon, France .
    Thierry-jebali, Nicolas
    University of Lyon, France .
    Lazar, Mihai
    University of Lyon, France .
    Planson, Dominique
    University of Lyon, France .
    Brosselard, Pierre
    University of Lyon, France .
    ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Vergne, Bertrand
    French-German Research Institute of Saint-Louis (ISL), France.
    Scharnholz, Sigo
    German Research Institute of Saint-Louis (ISL), France.
    600 V PiN diodes fabricated using on-axis 4H silicon carbide2012In: Materials Science Forum Vol 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 969-972Conference paper (Refereed)
    Abstract [en]

    This paper reports the fabrication and electrical characterization of PiN diodes on an on-axis grown epitaxial layer. TCAD simulations have been performed in order to design their architecture. Some of these diodes have a breakdown voltage around 600 V. A comparison is made with similar diodes fabricated on off-cut grown layers. Computer simulations are used to explain lower breakdown voltages than those expected.

  • 20.
    Hassan, Jawad
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lilja, Louise
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Booker, Ian Don
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Influence of Growth Mechanism on Carrier Lifetime in on-axis Homoepitaxial Layers of 4H-SiC2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 157-160Conference paper (Refereed)
    Abstract [en]

    In this report we present homoepitaxial growth of 4H-SiC on Si-face, nominally on-axis substrates with diameters up to 76 mm in a hot-wall chemical vapor deposition reactor. A comparatively low carrier lifetime has been observed in these layers; local variations in carrier lifetime are different from standard epilayers on off-cut substrates. The properties of the layers were studied with focus on charge carrier lifetime and its correlation with starting growth conditions, inhomogeneities of surface morphology and different growth mechanisms.

  • 21.
    Hassan, Jawad
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Scajev, Patrik
    Institute of Applied Research, Vilnius University, Vilnius, Lithuania.
    Jarasiunas, Kestutis
    Institute of Applied Research, Vilnius University, Vilnius, Lithuania.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Optically Detected Temperature Dependences of Carrier Lifetime and Diffusion Coefficient in 4H- and 3C-SiC2011In: Materials Science Forum (Volumes 679 - 680), Trans Tech Publications Inc., 2011, p. 205-208Conference paper (Refereed)
    Abstract [en]

    Free carrier dynamics has been studied in 4H- and 3C-SiC in a wide temperature range using time-resolved photoluminescence, free carrier absorption, and light induced transient grating techniques. Considerably high carrier lifetime was observed in 3C-SiC epitaxial layers grown on 4H-SiC substrates using hot-wall CVD with respect to previously reported values for 3C-SiC grown either on Si or on 6H-SiC substrates. The temperature dependences of carrier lifetime and diffusion coefficient for 4H- and 3C-SiC were compared. Shorter photoluminescence decay time with respect to free carrier absorption decay time was observed in the same 4H-SiC sample, while these techniques revealed similar trends in the carrier lifetime temperature dependencies. However, the latter dependences for hot-wall CVD-grown 3C layers were found different if measured by time resolved photoluminescence and free carrier absorption techniques.

  • 22.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Leone, Stefano
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kordina, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Jonas P.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Epitaxial growth on on-axis substrates2012In: Silicon Carbide Epitaxy / [ed] Francesco La Via, Kerala, India: Research Signpost, 2012, p. 97-119Chapter in book (Refereed)
    Abstract [en]

    SiC epitaxial growth using the Chemical Vapour Deposition (CVD) technique on nominally on-axis substrate is presented. Both standard and chloride-based chemistry have been used with the aim to obtain high quality layers suitable for device fabrication. Both homoepitaxy (4H on 4H) and heteroepitaxy (3C on hexag onal substrate) are addressed.

  • 23.
    Henry, Anne
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Thick Silicon Carbide Homoepitaxial Layers Grown by CVD Techniques2006In: Chemical Vapor Deposition, ISSN 0948-1907, E-ISSN 1521-3862, Vol. 12, no 8-9, p. 475-482Article in journal (Refereed)
  • 24.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Beyer, Franziska
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Andersson, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Godignon, P.
    Thick epilayers for power devices2007In: Materials Science Forum, vol. 556-557, Trans Tech Publications , 2007, p. 47-Conference paper (Refereed)
    Abstract [en]

    Growth of thick epitaxial SiC layers needed for high power devices is presented for horizontal hot-wall CVD (HWCVD) reactors. We demonstrate thickness of epilayer of 100 μm and more with good morphology, low-doping with no doping variation through the whole thick layer and reasonable carrier lifetime which mainly depends on the substrate quality. Typical epidefects are described and their density can dramatically be reduced when choosing correctly the growth conditions as well as the polishing of the surface prior to the growth. The control of the doping and thickness uniformities as well as the run-to-run reproducibility is also presented. Various characterization techniques such as optical microscopy, AFM, reflectance, CV, PL and minority carrier lifetime have been used. Results of high-voltage SiC Schottky power devices are presented.

  • 25.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Zakharov, Alexei A.
    Lund University, Sweden .
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Layer-number determination in graphene on SiC by reflectance mapping2014In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 77, p. 492-500Article in journal (Refereed)
    Abstract [en]

    We report a simple, handy and affordable optical approach for precise number-of-layers determination of graphene on SiC based on monitoring the power of the laser beam reflected from the sample (reflectance mapping) in a slightly modified micro-Raman setup. Reflectance mapping is compatible with simultaneous Raman mapping. We find experimentally that the reflectance of graphene on SiC normalized to the reflectivity of bare substrate (the contrast) increases linearly with similar to 1.7% per layer for up to 12 layers, in agreement with theory The wavelength dependence of the contrast in the visible is investigated using the concept of ideal fermions and compared with existing experimental data for the optical constants of graphene. We argue also that the observed contrast is insensitive to the doping condition of the sample, as well as to the type of sample (graphene on C- or Si-face of 4H or 6H SiC, hydrogen-intercalated graphene). The possibility to extend the precise layer counting to similar to 50 layers makes reflectivity mapping superior to low-energy electron microscopy (limited to similar to 10 layers) in quantitative evaluation of graphene on the C-face of SiC. The method is applicable for graphene on other insulating or semiconducting substrates.

  • 26.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Temperature Dependence and Selective Excitation of the Phosphorus Related Photoluminescence in 4H-SiC2009In: Materials Science Forum, Vols. 615-617, Trans Tech Publications , 2009, p. 263-266Conference paper (Refereed)
    Abstract [en]

    The paper presents experimental data on the temperature dependence and the excitation properties of the phosphorus-related photoluminescence in 4H SiC. Two main sets of phonon replicas can be observed with selective excitation, which are attributed to two of the no-phonon lines observed in the spectrum. Some of the excited states are also attributed to one of the no-phonon lines on the ground of the selectively excited spectra. A tentative explanation of the observed features in terms of multiple bound excitons is proposed.

  • 27.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yazdanfar, Milan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lundqvist, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Chen, Jr-Tai
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Stenberg, Pontus
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ager, Joel W. III
    Lawrence Berkeley National Laboratory, Berkeley, California, USA.
    Kordina, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    High-Resolution Raman and Luminescence Spectroscopy of Isotope-Pure (SiC)-Si-28-C-12, Natural and C-13 - Enriched 4H-SIC2014In: Silicon Carbide and Related Materials 2013, PTS 1 AND 2, Trans Tech Publications Inc., 2014, Vol. 778-780, p. 471-474Conference paper (Refereed)
    Abstract [en]

    The optical properties of isotope-pure (SiC)-Si-28-C-12, natural SiC and enriched with C-13 isotope samples of the 4H polytype are studied by means of Raman and photoluminescence spectroscopies. The phonon energies of the Raman active phonons at the Gamma point and the phonons at the M point of the Brillouin zone are experimentally determined. The excitonic bandgaps of the samples are accurately derived using tunable laser excitation and the phonon energies obtained from the photoluminescence spectra. Qualitative comparison with previously reported results on isotope-controlled Si is presented.

  • 28.
    Janzén, Erik
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Danielsson, Örjan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Forsberg, Urban
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Kakanakova-Gueorguie, Anelia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Persson, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Wahab, Qamar Ul
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    SiC and III-nitride Growth in a Hot-wall CVD Reactor2005In: Materials Science Forum, ISSN 0255-5476, volume 483-485, Trans Tech Publications , 2005, Vol. 483-485, p. 61-66Conference paper (Refereed)
  • 29.
    Johansson, Leif
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Xia, Chao
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Zarharov, Alexei A.
    MAX-lab, Lund University, Lund 22100, Sweden.
    Watcharinyanon, Somsakul
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Virojanadara, Chariya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Is the Registry Between Adjacent Graphene Layers Grown on C-Face SiC Different Compared to That on Si-Face SiC2013In: Crystals, ISSN 2073-4352, Vol. 3, no 1, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Graphene grown on C-face SiC substrates using two procedures, high and low growth temperature and different ambients, was investigated using Low Energy Electron Microscopy (LEEM), X-ray Photo Electron Electron Microscopy (XPEEM), selected area Low Energy Electron Diffraction (μ-LEED) and selected area Photo Electron Spectroscopy (μ-PES). Both types of samples showed formation of μm-sized grains of graphene. The sharp (1 × 1) μ-LEED pattern and six Dirac cones observed in constant energy photoelectron angular distribution patterns from a grain showed that adjacent layers are not rotated relative to each other, but that adjacent grains in general have different azimuthal orientations. Diffraction spots from the SiC substrate appeared in μ-LEED patterns collected at higher energies, showing that the rotation angle between graphene and SiC varied. C 1s spectra collected did not show any hint of a carbon interface layer. A hydrogen treatment applied was found to have a detrimental effect on the graphene quality for both types of samples, since the graphene domain/grain size was drastically reduced. From hydrogen treated samples, μ-LEED showed at first a clear (1 × 1) pattern, but within minutes, a pattern containing strong superstructure spots, indicating the presence of twisted graphene layers. The LEED electron beam was found to induce local desorption of hydrogen. Heating a hydrogenated C-face graphene sample did not restore the quality of the original as-grown sample.

  • 30.
    Kallinger, B.
    et al.
    Fraunhofer IISB, Erlangen, Germany.
    Rommel, M.
    Fraunhofer IISB, Erlangen, Germany.
    Lilja, Louise
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Booker, Ian Don
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Comparison of carrier lifetime measurements and mapping in 4H SIC using time resolved photoluminescence and μ-PCD2014In: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2, Stafa-Zurich, Switzerland: Trans Tech Publications , 2014, Vol. 778-780, p. 301-304Conference paper (Refereed)
    Abstract [en]

    Carrier lifetime measurements and wafer mappings have been done on several different 4H SiC epiwafers to compare two different measurement techniques, time-resolved photoluminescence and microwave induced photoconductivity decay. The absolute values of the decay time differ by a factor of two, as expected from recombination and measurement theory. Variations within each wafer are comparable with the two techniques. Both techniques are shown to be sensitive to substrate quality and distribution of extended defects.

  • 31.
    Karhu, Robin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Booking, Ian
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    The Role of Chlorine during High Growth Rate Epitaxy2015In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 821-823, p. 141-144Article in journal (Refereed)
    Abstract [en]

    The influence of chlorine has been investigated for high growth rates of 4H-SiC epilayers on 4o off-cut substrates. Samples were grown at a growth rate of approximately 50 and 100 μm/h and various Cl/Si ratios. The growth rate, net doping concentration and charge carrier lifetime have been studied as a function of Cl/Si ratio. This study shows some indications that a high Cl concentration in the growth cell leads to less availability of Si during the growth process.

  • 32.
    Li, Xun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kordina, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Surface preparation of 4 degrees off-axis 4H-SIC substrate for epitaxial growth2013In: Materials Science Forum (Volumes 740 - 742), Trans Tech Publications Inc., 2013, p. 225-228Conference paper (Refereed)
    Abstract [en]

    Results of surface preparation on Si-face 4° off-cut 4H-SiC substrates are presented in this paper. The influences of two types of etchants, i.e. hydrogen chloride (HCl) and only hydrogen (H2), were investigated by Nomarski microscopy and AFM. The experiments were performed in a hot wall CVD reactor using a TaC coated susceptor. Four etching temperatures, including 1580 °C, 1600 °C, 1620 °C and 1640 °C, were studied. In-situ etching with only H2 as ambient atmosphere is found to be the optimal way for the SiC surface preparation. Using HCl at temperature higher than 1620 °C could degrade the substrates surface quality.

  • 33.
    Lilja, Louise
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Don Booker, Ian
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    The influence of growth conditions on carrier lifetime in 4H-SiC epilayers2013In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 381, p. 43-50Article in journal (Refereed)
    Abstract [en]

    4H-SiC homoepitaxial layers have been grown in a horizontal hot-wall CVD (chemical vapor deposition) reactor and the measured carrier lifetimes have been correlated to the CVD growth conditions. Two different generations of reactors were compared, resulting in measured carrier lifetimes in two different orders of magnitude, from a few hundreds of ns to a few ms. The variations in measured carrier lifetime were correlated to deep level concentrations of the Z(1/2) center and the D-1 center, seen by photoluminescence. Decreasing the growth temperature clearly prolonged the carrier life time and showed lower Z(1/2) concentrations, where as lowering the growth rate only showed a small improvement of the carrier lifetime and no obvious tendencyin Z(1/2) defect concentrations, indicating that Z(1/2) is not the only defect limiting the carrier lifetime. Increasing the C/Si ratio resulted in decreasing Z(1/2) concentrations, indicating the carbon vacancy nature of the defect. However, carrier lifetime measurements showed maximum values for a C/Si ratio of 1 but otherwise an increasing tendency for increasing C/Si ratios. The reactor giving higher carrier lifetimes, correspondingly also showed lower Z(1/2) concentrations indicating the lifetime limiting property of Z(1/2). Furthermore, the D-1 defect intensity increased with growth temperature and decreased with increasing C/Si ratio, similar to the Z(1/2) concentration.

  • 34.
    Lilja, Louise
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Booker, Ian
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Influence of Growth Temperature on Carrier Lifetime in 4H-SiC Epilayers2013Conference paper (Refereed)
    Abstract [en]

    Carrier lifetime and formation of defects have been investigated as a function of growth temperature in n-type 4H-SiC epitaxial layers, grown by horizontal hot-wall CVD. Emphasis has been put on having fixed conditions except for the growth temperature, hence growth rate, doping and epilayer thickness were constant in all epilayers independent of growth temperature. An increasing growth temperature gave higher Z1/2 concentrations along with decreasing carrier lifetime. A correlation between growth temperature and D1 defect was also observed.

  • 35.
    Lilja, Louise
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Booker, Ian D.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    The Effect of Growth Conditions on Carrier Lifetime in n-type 4H-SiC Epitaxial Layers2012In: Materials Science Forum Vol 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 161-164Conference paper (Refereed)
    Abstract [en]

    Carrier lifetime has been studied as a function of C/Si ratio and growth rate during epitaxial growth of n-type 4H-SiC using horizontal hot-wall CVD. Effort has been put on keeping all growth parameters constant with the exception of the parameter that is intended to vary. The carrier lifetime is found to decrease with increasing growth rate and the highest carrier lifetime is found for a C/Si ratio of 1. The surface roughness was correlated with epitaxial growth conditions with AFM analysis.

  • 36.
    Lilja, Louise
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Improved Epilayer Surface Morphology on 2 degrees off-cut 4H-SiC Substrates2014In: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2, Trans Tech Publications , 2014, Vol. 778-780, p. 206-209Conference paper (Refereed)
    Abstract [en]

    Homoepitaxial layers of 4H-SiC were grown with horizontal hot-wall CVD on 2 degrees off-cut substrates, with the purpose of improving the surface morphology of the epilayers and reducing the density of surface morphological defects. In-situ etching conditions in either pure hydrogen or in a mixture of silane and hydrogen prior to the growth were compared as well as C/Si ratios in the range 0.8 to 1.0 during growth. The smoothest epilayer surface, together with lowest defect density, was achieved with growth at a C/Si ratio of 0.9 after an in-situ etching in pure hydrogen atmosphere.

  • 37.
    Lilja, Louise
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    In-grown stacking-faults in 4H-SiC epilayers grown on 2 degrees off-cut substrates2015In: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 252, no 6, p. 1319-1324Article in journal (Refereed)
    Abstract [en]

    4H-SiC epilayers were grown on 2 degrees off-cut substrates using standard silane/propane chemistry, with the aim of characterizing in-grown stacking faults. The stacking faults were analyzed with low temperature photoluminescence spectroscopy, room temperature photoluminescence mappings, room temperature cathodoluminescence and synchrotron white beam X-ray topography. At least three different types of in-grown stacking faults were observed, including double Shockley stacking faults, triple Shockley stacking faults and bar-shaped stacking faults. Those stacking faults are all previously found in 4 degrees and 8 degrees off-cut epilayers; however, the geometrical size is larger in epilayers grown on 2 degrees off-cut substrates due to lower off-cut angle. The stacking faults were formed close to the epilayer/substrate interface during the epitaxial growth. (C) 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim

  • 38.
    Lisesivdin, S. B.
    et al.
    Gazi University, Turkey .
    Atmaca, G.
    Gazi University, Turkey .
    Arslan, E.
    Bilkent University, Turkey .
    Cakmakyapan, S.
    Bilkent University, Turkey .
    Kazar, O.
    Bilkent University, Turkey .
    Butun, S.
    Bilkent University, Turkey Northwestern University, IL 60208 USA .
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ozbay, E.
    Bilkent University, Turkey Bilkent University, Turkey Bilkent University, Turkey .
    Extraction and scattering analyses of 2D and bulk carriers in epitaxial graphene-on-SiC structure2014In: Physica. E, Low-Dimensional systems and nanostructures, ISSN 1386-9477, E-ISSN 1873-1759, Vol. 63, p. 87-92Article in journal (Refereed)
    Abstract [en]

    Hall effect measurements of a graphene-on-SiC system were carried out as a function of temperature (1.8-200 K) at a static magnetic field (0.51) With the analysis of temperature dependent single-field Hall data with the Simple Parallel Conduction Extraction Method (SPCEM), bulk and two-dimensional (2D) carrier densities and mobilities were extracted successfully. Bulk carrier is attributed to SIC substrate and 2D carrier is attributed to the graphene layer. For each SPCEM extracted carrier data, relevant three-dimensional or 2D scattering analyses were performed. Each SPCEM extracted carrier data were explained with the related scattering analyses. A temperature independent mobility component, which may related to an interaction between graphene and SIC, was observed for both scattering analyses with the same mobility limiting value. With the SPCEM, effective ionized impurity concentration of SiC substrate, extracted 2D-mobility, and sheet carrier density of the graphene layer are calculated with using temperature dependent static magnetic field Hall data.

  • 39.
    Nguyen, Son Tien
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Carlsson, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Umeda, T.
    Graduate School of Library, Information and Media Studies, University of Tsukuba, Tsukuba, Japan.
    Isoya, J.
    Graduate School of Library, Information and Media Studies, University of Tsukuba, Tsukuba, Japan.
    Gali, A.
    Department of Atomic Physics, Budapest University of Technology and Economics, Budapest, Hungary.
    Bockstedte, M.
    Universität Erlangen-Nürnberg, Erlangen, Germany, and Universidad del País Vasco, San Sebastián, Spain.
    Morishita, N.
    Japan Atomic Energy Research Institute, Takasaki, Japan.
    Ohshima, T.
    Japan Atomic Energy Research Institute, Takasaki, Japan.
    Itoh, H.
    Japan Atomic Energy Research Institute, Takasaki, Japan.
    Divacancy in 4H-SiC2006In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 96, no 5, p. 055501-1-055501-4, article id 055501Article in journal (Refereed)
    Abstract [en]

    Electron paramagnetic resonance and ab initio supercell calculations suggest that the P6/P7 centers, which were previously assigned to the photoexcited triplet states of the carbon vacancy-antisite pairs in the double positive charge state, are related to the triplet ground states of the neutral divacancy. The spin density is found to be located mainly on three nearest C neighbors of the silicon vacancy, whereas it is negligible on the nearest Si neighbors of the carbon vacancy.

  • 40.
    Nguyen, Son Tien
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Carlsson, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Defects and carrier compensation in semi-insulating 4H-SiC substrates2007In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 75, no 15Article in journal (Refereed)
    Abstract [en]

    Electron paramagnetic resonance (EPR) studies revealed that vacancies (VC and VSi), carbon vacancy-antisite pairs (VC CSi) and the divacancy (VC VSi) are common defects in high-purity semi-insulating (HPSI) 4H-SiC substrates. Their concentrations and some of their deep acceptor levels were estimated by EPR and photoexcitation EPR. The commonly observed thermal activation energies, Ea ∼0.8-0.9 eV, ∼1.1 eV, ∼1.25-1.3, and ∼1.5 eV, as determined from the temperature dependence of the resistivity, in different types of HPSI substrates were associated to different deep acceptor levels of VSi, VC, VC CSi, and VC VSi. The annealing behavior of these vacancy-related defects and their interaction at high temperatures (up to 1600°C) in HPSI materials were studied. Carrier compensation processes were proposed to explain the observed change of the thermal activation energy due to high temperature annealing. VC and VC VSi were suggested to be suitable defects for controlling the SI properties whereas the incorporation of VSi and VC CSi during the crystal growth or processing should be avoided for achieving stable HPSI materials. © 2007 The American Physical Society.

  • 41.
    Pedersen, Henrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Beyer, Franziska
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Donor incorporation in SiC epilayers grown at high growth rate with chloride-based CVD2009In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 311, no 5, p. 1321-1327Article in journal (Refereed)
    Abstract [en]

    A systematic n-type doping study has been performed on 4H- and 6H-SiC epilayers grown at high growth rate using chloride-based CVD. The effect of temperature, pressure, growth rate, C/Si-, Cl/Si ratio and dopant flow on the incorporation of the nitrogen and phosphorus donor atoms have been investigated. It is found that the effect of the C/Si-ratio on the incorporation of nitrogen or phosphorus atoms is similar to what has been reported for the standard low growth rate process without addition of chlorine. The Cl/Si-ratio seems to affect the nitrogen incorporation at growth rates higher than 65 μm/h. The doping concentration is stable against variations in growth rate, growth pressure and growth temperature for the nitrogen doped layers.

  • 42.
    Pedersen, Henrik
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Growth and Photoluminescence study of Aluminium doped SiC epitaxial layers2007In: Materials Science Forum, Vols. 556-557, Trans Tech Publications , 2007, p. 97-Conference paper (Refereed)
  • 43.
    Perez-Tomas, A
    et al.
    CNM CSIC, Spain.
    Brosselard, P
    CNM CSIC, Spain.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jorda, X
    CNM CSIC, Spain.
    Godignon, P
    CNM CSIC, Spain.
    Placidi, M
    CNM CSIC, Spain.
    Constant, A
    CNM CSIC, Spain.
    Millan, J
    CNM CSIC, Spain.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Schottky versus bipolar 3.3 kV SiC diodes2008In: SEMICONDUCTOR SCIENCE AND TECHNOLOGY, ISSN 0268-1242, Vol. 23, no 12, p. 125004-Article in journal (Refereed)
    Abstract [en]

    A comparative study of the electrical characteristics of 3.3 kV SiC Schottky barrier (SBD), junction bipolar Schottky (JBS) and PiN diodes is presented. 3.3 kV class 4H-SiC SBD, JBS and PiN diodes have been fabricated with an analogous technology process on similar epi wafers. Diodes have been characterized in forward, reverse and switching mode in the 25 degrees C - 300 degrees C temperature range. The optimum performance of the diodes depends on the adequate use of the unipolar or bipolar advantages and is established by the final application specifications. In this respect, a reverse recovery charge versus on-resistance diagram for different current densities is also presented. DC stress tests have been performed to investigate the forward voltage drift, related to the formation of stacking faults, during the bipolar mode of operation.

  • 44.
    Peyre, Hervé
    et al.
    Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Groupe d’Etudes des Semiconducteurs, Université Montpellier 2 and CNRS, cc 074‐GES, 34095 Montpellier Cedex 5, France.
    Guelfucci, Jude
    Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France.
    Juillaguet, Sandrine
    Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France.
    Ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Contreras, S.
    CNRS, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France.
    Brosselard, Pierre
    Laboratoire des Multimateriaux et Interfaces, UMR-CNRS 5615, UCB-Lyon1, 43 Bd du 11 nov. 1918, 69622 Villeurbanne, France.
    Camassel, Jean
    CNRS, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France.
    Low Temperature Photoluminescence Investigation of 3-Inch SiC Wafers for Power Device Applications2012In: HeteroSiC & WASMPE 2011, 2012, Vol. 711, p. 164-168Conference paper (Refereed)
    Abstract [en]

    Focusing on the change in aluminium-related photoluminescence lines in 4H-SiC versus doping concentration, we have used a combination of LTPL (Low Temperature PhotoLuminescence) and secondary ion mass spectrometry measurements to set new calibration curves. In this way, one can probe the change in aluminum concentration in the range 1017 to 1019 cm-3. When applied to LTPL maps collected on full 3-inch wafers, we show that such abacuses constitute a powerful tool to control efficiently the doping level of as-grown p+ (emitters) and p++ (contact) layers for power device applications.

  • 45.
    Salemi, A.
    et al.
    KTH Royal Institute of Technology, Kista, Sweden.
    Buono, B.
    Fairchild Semiconductor, Kista, Sweden.
    Hallen, A.
    KTH Royal Institute of Technology, Kista, Sweden.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Zetterling, C.M.
    KTH Royal Institute of Technology, Kista, Sweden.
    Östling, M.
    KTH Royal Institute of Technology, Kista, Sweden.
    Fabrication and design of 10 kV PiN diodes using on-axis 4H-SiC2014In: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2, Trans Tech Publications , 2014, Vol. 778-780, p. 836-840Conference paper (Refereed)
    Abstract [en]

    10 kV PiN diodes using on-axis 4H-SiC were designed, fabricated, and measured. A lifetime enhancement procedure was done by carbon implantation followed by high temperature annealing to increase lifetime to above 2 μs. The device simulation software Sentaurus TCAD has been used in order to optimize the diode. All fabricated diodes are fully functional and have a VF of 3.3 V at 100 A/cm2 at 25C, which was decreased to 3.0 V at 300C.

  • 46.
    Salemi, Arash
    et al.
    KTH Royal Institute Technology Integrated Devices and Circu, Sweden.
    Elahipanah, Hossein
    KTH Royal Institute Technology Integrated Devices and Circu, Sweden.
    Buono, Benedetto
    Fairchild Semicond, Sweden.
    Hallen, Anders
    KTH Royal Institute Technology Integrated Devices and Circu, Sweden.
    Ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Malm, Gunnar
    KTH Royal Institute Technology Integrated Devices and Circu, Sweden.
    Zetterling, Carl-Mikael
    KTH Royal Institute Technology Integrated Devices and Circu, Sweden.
    Ostling, Mikael
    KTH Royal Institute Technology Integrated Devices and Circu, Sweden.
    Conductivity Modulated On-axis 4H-SiC 10+kV PiN Diodes2015In: 2015 IEEE 27TH INTERNATIONAL SYMPOSIUM ON POWER SEMICONDUCTOR DEVICES and ICS (ISPSD), IEEE , 2015, p. 269-272Conference paper (Refereed)
    Abstract [en]

    Degradation-free ultrahigh-voltage (> 10 kV) PiN diodes using on-axis 4H-SiC with low forward voltage drop (V-F = 3.3 V at 100 A/cm(2)) and low differential on-resistance (R-ON = 3.4 m Omega.cm(2)) are fabricated, measured, and analyzed by device simulation. The devices show stable on-state characteristics over a broad temperature range up to 300 degrees C. They show no breakdown up to 10 kV, i.e., the highest blocking capability for 4H-SiC devices using on-axis to date. The minority carrier lifetime (tau(P)) is measured after epitaxial growth by time resolved photoluminescence (TRPL) technique at room temperature. The tau(P) is measured again after device fabrication by open circuit voltage decay (OCVD) up to 500 K.

  • 47. Shishkin, Y.
    et al.
    Rao, S.P.
    Kordina, O.
    Agafonov, I.
    Maltsev, A.A.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Moisson, C.
    Saddow, S.E.
    CVD of 6H-SiC on Non-Basal Quasi Polar Faces2007In: ECSCRM 2006,2006, Materials Science Forum: Trans Tech Publications , 2007, p. 73-Conference paper (Refereed)
  • 48.
    Sudow, M.
    et al.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Nemati, H.M.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Thorsell, M.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Gustavsson, U.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Andersson, K.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Fager, C.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Nilsson, P.-A.
    Nilsson, P.-Å., Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    ul-Hassan, Jawad
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Jos, R.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden, NXP Semiconductors BV, 5656 Eindhoven, Netherlands.
    Rorsman, N.
    Microwave Electronics Laboratory, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    SiC varactors for dynamic load modulation of high power amplifiers2008In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 29, no 7, p. 728-730Article in journal (Refereed)
    Abstract [en]

    SiC Schottky diode varactors with a high breakdown voltage, a high tuning ratio, and a low series resistance have been designed and fabricated. These characteristics are particularly necessary for the dynamic load modulation of high power amplifiers (PAs), which is an attractive alternative to other efficiency enhancement techniques. For a SiC Schottky diode varactor with a 50-µm radius fabricated by using a graded doping profile, a breakdown voltage of 40 V, a tuning range of 5.6, and a series resistance of 0.9 O were achieved. The results show the great potential of this type of varactors for the use in the dynamic load modulation of high power amplifiers. © 2008 IEEE.

  • 49.
    Thierry-Jebali, N
    et al.
    University of Lyon, France .
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lazar, M
    University of Lyon, France .
    Planson, D
    University of Lyon, France .
    Bano, E
    Grenoble INP, France .
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Brosselard, P
    University of Lyon, France .
    Observation of the generation of stacking faults and active degradation measurements on off-axis and on-axis 4H-SiC PiN diodes2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, no 22, p. 222111-Article in journal (Refereed)
    Abstract [en]

    PiN diodes have been fabricated on nominally on-axis Si-face 4H-SiC material and their electrical characteristics are compared to PiN diodes processed with exactly the same device process recipe on 8 degrees-off 4H-SiC material. Some diodes had an optical window on the top metal contact to observe the possible stacking faults generation and motion with photo emission microscopy. The diodes were electrically characterized in forward voltage to test their stability. Electrical characterizations demonstrate that there is no noticeable degradation for the diodes processed on on-axis 4H-SiC substrate and with optical characterization the formation of stacking faults was not observed.

  • 50.
    Thierry-Jebali, Nicolas
    et al.
    Université de Lyon, Villeurbanne Cedex, France.
    Lazar, Mihai
    Université de Lyon, Villeurbanne Cedex, France.
    Vo-Ha, Arthur
    Université de Lyon, Villeurbanne Cedex, France.
    Carole, Davy
    Université de Lyon, Villeurbanne Cedex, France.
    Souliere, Veronique
    Université de Lyon, Villeurbanne Cedex, France.
    Laariedh, Farah
    Université de Lyon, Villeurbanne Cedex, France.
    ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Janzen, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Planson, Dominique
    Université de Lyon, Villeurbanne Cedex, France.
    Ferro, Gabriel
    Université de Lyon, Villeurbanne Cedex, France.
    Brylinski, Christian
    Université de Lyon, Villeurbanne Cedex, France.
    Brosselard, Pierre
    Université de Lyon, Villeurbanne Cedex, France.
    Electrical Characterization of PiN Diodes with p(+) layer Selectively Grown by VLS Transport2013In: Silicon Carbide and Related Materials 2012 / [ed] Alexander A. Lebedev, Sergey Yu. Davydov, Pavel A. Ivanov and Mikhail E. Levinshtein, Trans Tech Publications Inc., 2013, Vol. 740-742, p. 911-914Conference paper (Refereed)
    Abstract [en]

    This paper deals with electrical characterization of PiN diodes fabricated on an 8 degrees off-axis 4H-SiC with a p(++) epitaxial area grown by Vapour-Liquid-Solid (VLS) transport. It provides for the first time evidence that a high quality p-n junction can be achieved by using this technique followed by a High Temperature Annealing (HTA) process.

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