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  • 1.
    Beyer, Franziska C.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Deep levels in SiC2011Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Silicon carbide (SiC) has been discussed as a promising material for high power bipolar devices for almost twenty years. Advances in SiC crystal growth especially the development of chemical vapor deposition (CVD) have enabled the fabrication of high quality material. Much progress has further been achieved in identifying minority charge carrier lifetime limiting defects, which may be attributed to structural defects, surface recombination or point defects located in the band gap of SiC.

    Deep levels can act as recombination centers by interacting with both the valence and conduction band. As such, the defect levels reduce the minority charge carrier lifetime, which is of great importance in bipolar devices.

    Impurities in semiconductors play an important role to adjust their semiconducting properties. Intentional doping can introduce shallow defect levels to increase the conductivity or deep levels for achieving semi-insulating (SI) SiC. Impurities, especially transition metals generate defect levels deep in the band gap of SiC, which trap charge carriers and thus reduce the charge carrier lifetime. Transition metals, such as vanadium, are used in SiC to compensate the residual nitrogen doping.

    It has previously been reported that valence band edges of the different SiC polytypes are pinned to the same level and that deep levels related to transition metals can serve as a common reference level; this is known as the LANGER-HEINRICH (LH) rule.

    Electron irradiation introduces or enhances the concentration of existing point defects, such as the carbon vacancy (VC) and the carbon interstitial (Ci). Limiting the irradiation energy, Eirr, below the displacement energy of silicon in the SiC lattice (Eirr < 220 keV), the generated defects can be attributed to carbon related defects, which are already created at lower Eirr. Ci are mobile at low temperatures and using low temperature heat treatments, the annealing behavior of the introduced Ci and their complexes can be studied.

    Deep levels, which appear and disappear depending on the electrical, thermal and optical conditions prior to the measurements are associated with metastable defects. These defects can exist in more than one configuration, which itself can have different charge states. Capacitance transient investigations, where the defect’s occupation is studied by varying the depletion region in a diode, can be used to observe such occupational changes. Such unstable behavior may influence device performance, since defects may be electrically active in one configuration and inactive after transformation to another configuration.

    This thesis is focused on electrical characterization of deep levels in SiC using deep level transient spectroscopy (DLTS). The first part, papers 1-4, is dedicated to defect studies of both impurities and intrinsic defects in as-grown material. The second part, consisting of papers 5-7, is dealing with the defect content after electron irradiation and the annealing behavior of the introduced deep levels.

    In the first part, transition metal incorporation of iron (Fe) and tungsten (W) is discussed in papers 1 and 2, respectively. Fe and W are possible candidates to compensate the residual nitrogen doping in SiC. The doping with Fe resulted in one level in n-type material and two levels in p-type 4H-SiC. The capture process is strongly coupled to the lattice. Secondary ion mass spectrometry measurements detected the presence of B and Fe. The defects are suggested to be related to Fe and/or Fe-B-pairs.

    Previous reports on tungsten doping showed that W gives rise to two levels (one shallow and one deep) in 4H- and only one deep level in 6H-SiC. In 3C-SiC, we detected two levels, one likely related to W and one intrinsic defect, labeled E1. The W related energy level aligns well with the deeper levels observed in 4H- and 6H-SiC in agreement with the LH rule.

    The LH rule is observed from experiments to be also valid for intrinsic levels. The level related to the DLTS peak EH6=7 in 4H-SiC aligns with the level related to E7 in 6H-SiC as well as with the level related to E1 in 3C-SiC. The alignment suggests that these levels may originate from the same defect, probably the VC, which has been proposed previously for 4H- and 6H-SiC.

    In paper 3, electrical characterization of 3C-layers grown heteroepitaxially on different SiC substrates is discussed. The material was of high quality with a low background doping concentration and SCHOTTKY diodes were fabricated. It was observed that nickel as rectifying contact material exhibits a similar barrier height as the previously suggested gold. A leakage current in the low nA range at a reverse bias of -2 V was achieved, which allowed capacitance transient measurements. One defect related to DLTS peak E1, previously presented in paper 2, was detected and suggested to be related to an intrinsic defect.

    Paper 4 gives the evidence that chloride-based CVD grown material yields the same kind of defects as reported for standard CVD growth processes. However, for very high growth rates, exceeding 100 mm/h, an additional defect is observed as well as an increase of the Ti-concentration. Based on the knowledge from paper 2, the origin of the additional peak and the assumed increase of Ti-concentration can instead both be attributed to the deeper and the shallower level of tungsten in 4H-SiC, respectively.

    In the second part of the thesis, studies of low-energy (200 keV) electron irradiated as-grown 4H-SiC were performed. In paper 5, bistable defects, labeled EB-centers, evolved in the DLTS spectrum after the annihilation of the irradiation induced defect levels related to DLTS peaks EH1, EH3 and the bistable M-center. In a detailed annealing study presented in paper 6, the partial transformation of M-centers into the EB-centers is discussed. The transition between the two defects (M-centers → EB-centers) takes place at rather low temperatures (T ≈ 400 oC), which suggests a mobile defect as origin. The M-center and the EB-centers are suggested to be related to Ci and/or Ci complex defects. The EB-centers anneal out at about 700 oC.

    In paper 7, the DLTS peak EH5, which is observed after low- and high-energy electron irradiation is presented. The peak is associated with a bistable defect, labeled F-center. Configuration A exists unoccupied and occupied by an electron, whereas configuration B is only stable when filled by an electron. Reconfiguration temperatures for both configurations were determined and the reconfiguration energies were calculated from the transition kinetics. The reconfiguration B→A can also be achieved by minority charge carrier injection. The F-center is likely a carbon related defect, since it is already present after low-energy irradiation.

    Delarbeten
    1. Deep levels in iron doped n- and p-type 4H-SiC
    Öppna denna publikation i ny flik eller fönster >>Deep levels in iron doped n- and p-type 4H-SiC
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    2011 (Engelska)Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 110, s. 123701-1-123701-5Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Deep levels were detected in Fe-doped n- and p-type 4H-SiC using deep level transient spectroscopy (DLTS). One defect level (EC 0.39 eV) was detected in n-type material. DLTS spectra of p-type 4H-SiC show two dominant peaks (EV + 0.98 eV and EV + 1.46 eV). Secondary ion mass spectrometry measurements confirm the presence of Fe in both n- and p-type 4H-SiC epitaxial layers. The majority capture process for all the three Fe-related peaks is multi-phonon assisted. Similar defect behavior in Si indicates that the observed DLTS peaks are likely related to Fe and Fe-B pairs.

    Ort, förlag, år, upplaga, sidor
    American Institute of Physics (AIP), 2011
    Nyckelord
    crystal microstructure, vacancies, defects, radiation effects, semiconductors
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-70352 (URN)10.1063/1.3669401 (DOI)000298639800044 ()
    Anmärkning
    funding agencies|Swedish Research Council (VR)||Swedish Energy Agency||Tillgänglig från: 2011-09-02 Skapad: 2011-09-02 Senast uppdaterad: 2017-12-08Bibliografiskt granskad
    2. Deep levels in tungsten doped n-type 3C-SiC
    Öppna denna publikation i ny flik eller fönster >>Deep levels in tungsten doped n-type 3C-SiC
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    2011 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 98, nr 15, s. 152104-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Tungsten was incorporated in SiC and W related defects were investigated using deep level transient spectroscopy. In agreement with literature, two levels related to W were detected in 4H-SiC, whereas only the deeper level was observed in 6H-SiC. The predicted energy level for W in 3C-SiC was observed (E-C-0.47 eV). Tungsten serves as a common reference level in SiC. The detected intrinsic levels align as well: E1 (E-C-0.57 eV) in 3C-SiC is proposed to have the same origin, likely V-C, as EH6/7 in 4H-SiC and E7 in 6H-SiC, respectively.

    Ort, förlag, år, upplaga, sidor
    American Institute of Physics, 2011
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-67976 (URN)10.1063/1.3579527 (DOI)000289580800030 ()
    Anmärkning
    Original Publication: Franziska Beyer, Carl Hemmingsson, Andreas Gällström, Stefano Leone, Henrik Pedersen, Anne Henry and Erik Janzén, Deep levels in tungsten doped n-type 3C-SiC, 2011, APPLIED PHYSICS LETTERS, (98), 15, 152104. http://dx.doi.org/10.1063/1.3579527 Copyright: American Institute of Physics http://www.aip.org/ Tillgänglig från: 2011-05-04 Skapad: 2011-05-04 Senast uppdaterad: 2017-12-11
    3. Deep levels in hetero-epitaxial as-grown 3C-SiC
    Öppna denna publikation i ny flik eller fönster >>Deep levels in hetero-epitaxial as-grown 3C-SiC
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    2010 (Engelska)Ingår i: AIP Conference Proceedings, Vol. 1292, 2010, s. 63-66Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    3C-SiC grown hetero-epitaxially on 4H- or 6H-SiC using a standard or a chloride-based CVD process were electrically characterized using IV, CV and DLTS. The reverse leakage current of the Au-Schottky diodes was  reduced to lower than 10-8 A at -2V by a thermal oxidation step using UV-light illumination at 200oC. The Schottky barrier height of the Ni and Au contacts were determined by IV measurement to be ØB = 0.575  eV and ØB = 0.593 eV, respectively, for a contact diameter of about 150 mm. One dominant DLTS peak was observed in the 3C-epilayers independently of the substrate at about EC0:60 eV which is attributed to W6-level in 3C-SiC. This deep level is thought to be related to an intrinsic defect.

    Nyckelord
    Deep levels, 3C-SiC, hetero-epitaxial, chloride-based CVD
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-64425 (URN)10.1063/1.3518312 (DOI)978-073540847-0 (ISBN)
    Konferens
    E-MRS Symposium F on 2010 Wide Bandgap Cubic Semiconductors: From Growth to Devices, 2010
    Tillgänglig från: 2011-01-24 Skapad: 2011-01-24 Senast uppdaterad: 2015-09-22Bibliografiskt granskad
    4. Defects in 4H-SiC Layers Grown by Chloride-based Epitaxy
    Öppna denna publikation i ny flik eller fönster >>Defects in 4H-SiC Layers Grown by Chloride-based Epitaxy
    2009 (Engelska)Ingår i: Materials Science Forum Vols. 615-617 / [ed] Amador Pérez-Tomás, Trans Tech Publications , 2009, s. 373-Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Chloride-based 4H-SiC epitaxial layers were investigated by DLTS, MCTS and PL. The DLTS spectra of the as grown samples showed dominance of the Z1/2 and the EH6/7 peaks. For growth rates exceeding 100 µm/h, an additional peak occurred in the DLTS spectra which can be assigned to the UT1 defect. The shallow and the deep boron complexes as well as the HS1 defect are observed in MCTS measurements. The PL spectra are completely dominated by the near band gap (NBG) emission. No luminescence from donor-acceptor pair occurred. The PL line related to the D1 centre was weakly observed. In the NBG region nitrogen bound exciton (N-BE) and free exciton (FE) related lines could be seen. The addition of chlorine in the growth process gives the advantage of high growth rates without the introduction of additional defects.

    Ort, förlag, år, upplaga, sidor
    Trans Tech Publications, 2009
    Nationell ämneskategori
    Naturvetenskap Den kondenserade materiens fysik
    Identifikatorer
    urn:nbn:se:liu:diva-45290 (URN)10.4028/www.scientific.net/MSF.615-617.373 (DOI)80732 (Lokalt ID)80732 (Arkivnummer)80732 (OAI)
    Konferens
    European Conference on Silicon Carbide and Related Materials, 7-11 September, Barcelona, Spain
    Tillgänglig från: 2009-10-10 Skapad: 2009-10-10 Senast uppdaterad: 2015-03-11Bibliografiskt granskad
    5. Bistable defects in low-energy electron irradiated n-type 4H-SiC
    Öppna denna publikation i ny flik eller fönster >>Bistable defects in low-energy electron irradiated n-type 4H-SiC
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    2010 (Engelska)Ingår i: PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS, ISSN 1862-6254, Vol. 4, nr 8-9, s. 227-229Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Epitaxial n-type 4H-SiC layers were irradiated at room temperature by low-energy electrons. During the annihilation process of the irradiation induced defects EH I and EH3, three new bistable centers, labeled EB centers, were detected in the DLTS spectrum. The reconfigurations of the EB centers (I -andgt; II and II -andgt; I) take place at room temperature with a thermal reconfiguration energy of about 0.95 eV. The threshold energy for moving the Si atom from its site in the SiC crystal structure is higher than the applied irradiation energy; therefore, the EB centers are attributed to carbon related complex defects.

    Ort, förlag, år, upplaga, sidor
    John Wiley and Sons, Ltd, 2010
    Nyckelord
    crystal microstructure, vacancies, defects, radiation effects, semiconductors
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-60692 (URN)10.1002/pssr.201004249 (DOI)000282541400015 ()
    Tillgänglig från: 2010-11-01 Skapad: 2010-10-22 Senast uppdaterad: 2015-09-22Bibliografiskt granskad
    6. Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC
    Öppna denna publikation i ny flik eller fönster >>Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC
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    2011 (Engelska)Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, nr 10, s. 103703-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    After low-energy electron irradiation of epitaxial n-type 4H-SiC with a dose of 5 x 10(16) cm(-2), the bistable M-center, previously reported in high-energy proton implanted 4H-SiC, is detected in the deep level transient spectroscopy (DLTS) spectrum. The annealing behavior of the M-center is confirmed, and an enhanced recombination process is suggested. The annihilation process is coincidental with the evolvement of the bistable EB-centers in the low temperature range of the DLTS spectrum. The annealing energy of the M-center is similar to the generation energy of the EB-centers, thus partial transformation of the M-center to the EB-centers is suggested. The EB-centers completely disappeared after annealing temperatures higher than 700 degrees C without the formation of new defects in the observed DLTS scanning range. The threshold energy for moving Si atom in SiC is higher than the applied irradiation energy, and the annihilation temperatures are relatively low, therefore the M-center, EH1 and EH3, as well as the EB-centers are attributed to defects related to the C atom in SiC, most probably to carbon interstitials and their complexes.

    Ort, förlag, år, upplaga, sidor
    American Institute of Physics, 2011
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-69907 (URN)10.1063/1.3586042 (DOI)000292115900079 ()
    Anmärkning
    Original Publication: Franziska Beyer, Carl Hemmingsson, Henrik Pedersen, Anne Henry, Erik Janzén, J. Isoya, N. Morishita and T. Ohshima, Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC, 2011, Journal of Applied Physics, (109), 10, 103703. http://dx.doi.org/10.1063/1.3586042 Copyright: American Institute of Physics http://www.aip.org/ Tillgänglig från: 2011-08-09 Skapad: 2011-08-08 Senast uppdaterad: 2017-12-08
    7. Influence of background concentration induced field on the emission rate signatures of an electron trap in zinc oxide Schottky devices
    Öppna denna publikation i ny flik eller fönster >>Influence of background concentration induced field on the emission rate signatures of an electron trap in zinc oxide Schottky devices
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    2010 (Engelska)Ingår i: JOURNAL OF APPLIED PHYSICS, ISSN 0021-8979, Vol. 107, nr 10Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Various well-known research groups have reported points defects in bulk zinc oxide (ZnO) [N-D (intrinsic): 10(14)-10(17) cm(-3)] naming oxygen vacancy, zinc interstitial, and/or zinc antisite having activation energy in the range of 0.32-0.22 eV below conduction band. The attribution is probably based on activation energy of the level which seems not to be plausible in accordance with Vincent et al., [J. Appl. Phys. 50, 5484 (1979)] who suggested that it was necessary to become vigilant before interpreting the data attained for a carrier trap using capacitance transient measurement of diodes having ND greater than 10(15) cm(-3). Accordingly the influence of background free-carrier concentration, ND induced field on the emission rate signatures of an electron point defect in ZnO Schottky devices has been investigated by means of deep level transient spectroscopy. A number of theoretical models were tried to correlate with the experimental data to ascertain the mechanism. Consequently Poole-Frenkel model based on Coulomb potential was found consistent. Based on these investigations the electron trap was attributed to Zn-related charged impurity. Qualitative measurements like current-voltage and capacitance-voltage measurements were also performed to support the results.

    Ort, förlag, år, upplaga, sidor
    American Institute of Physics, 2010
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-57405 (URN)10.1063/1.3428426 (DOI)000278182400083 ()
    Anmärkning
    Original Publication: Hadia Noor, P Klason, Sadia Muniza Faraz, Omer Nour, Qamar Ul Wahab, Magnus Willander and M Asghar, Influence of background concentration induced field on the emission rate signatures of an electron trap in zinc oxide Schottky devices, 2010, JOURNAL OF APPLIED PHYSICS, (107), 10, 103717. http://dx.doi.org/10.1063/1.3428426 Copyright: American Institute of Physics http://www.aip.org/ Tillgänglig från: 2010-06-18 Skapad: 2010-06-18 Senast uppdaterad: 2014-01-15
  • 2.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Gällström, Andreas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Deep levels in tungsten doped n-type 3C-SiC2011Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 98, nr 15, s. 152104-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tungsten was incorporated in SiC and W related defects were investigated using deep level transient spectroscopy. In agreement with literature, two levels related to W were detected in 4H-SiC, whereas only the deeper level was observed in 6H-SiC. The predicted energy level for W in 3C-SiC was observed (E-C-0.47 eV). Tungsten serves as a common reference level in SiC. The detected intrinsic levels align as well: E1 (E-C-0.57 eV) in 3C-SiC is proposed to have the same origin, likely V-C, as EH6/7 in 4H-SiC and E7 in 6H-SiC, respectively.

  • 3.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lin, Y.-C.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Gällström, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Deep levels in iron doped n- and p-type 4H-SiC2011Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 110, s. 123701-1-123701-5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deep levels were detected in Fe-doped n- and p-type 4H-SiC using deep level transient spectroscopy (DLTS). One defect level (EC 0.39 eV) was detected in n-type material. DLTS spectra of p-type 4H-SiC show two dominant peaks (EV + 0.98 eV and EV + 1.46 eV). Secondary ion mass spectrometry measurements confirm the presence of Fe in both n- and p-type 4H-SiC epitaxial layers. The majority capture process for all the three Fe-related peaks is multi-phonon assisted. Similar defect behavior in Si indicates that the observed DLTS peaks are likely related to Fe and Fe-B pairs.

  • 4.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, J
    University of Tsukuba.
    Morishita, N
    Japan Atomic Energy Agency.
    Ohshima, T
    Japan Atomic Energy Agency.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Bistable defects in low-energy electron irradiated n-type 4H-SiC2010Ingår i: PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS, ISSN 1862-6254, Vol. 4, nr 8-9, s. 227-229Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial n-type 4H-SiC layers were irradiated at room temperature by low-energy electrons. During the annihilation process of the irradiation induced defects EH I and EH3, three new bistable centers, labeled EB centers, were detected in the DLTS spectrum. The reconfigurations of the EB centers (I -andgt; II and II -andgt; I) take place at room temperature with a thermal reconfiguration energy of about 0.95 eV. The threshold energy for moving the Si atom from its site in the SiC crystal structure is higher than the applied irradiation energy; therefore, the EB centers are attributed to carbon related complex defects.

  • 5.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, J
    University of Tsukuba, Japan .
    Morishita, N
    Japan Atom Energy Agency, Japan .
    Ohshima, T
    University of Tsukuba, Japan .
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Capacitance transient study of a bistable deep level in e(-)-irradiated n-type 4H-SiC2012Ingår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 45, nr 45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using capacitance transient techniques, a bistable centre, called FB centre here, was observed in electron irradiated 4H-SiC. In configuration A, the deep level known as EH5 (E-a = E-C - 1.07 eV) is detected in the deep level transient spectroscopy spectrum, whereas for configuration B no obvious deep level is observed in the accessible part of the band gap. Isochronal annealing revealed the transition temperatures to be T-A -andgt; B andgt; 730K and for the opposite process T-B -andgt; A approximate to 710 K. The energy needed to conduct the transformations were determined to be E-A(A -andgt; B) = (2.1 +/- 0.1) eV and E-A(B -andgt; A) = (2.3 +/- 0.1) eV, respectively. The pre-factor indicated an atomic jump process for the opposite transition A -andgt; B and a charge carrier-emission dominated process in the case of B -andgt; A. Minority charge carrier injection enhanced the transformation from configuration B to configuration A by lowering the transition barrier by about 1.4 eV. Since the bistable FB centre is already present after low-energy electron irradiation (200 keV), it is likely related to carbon.

  • 6.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, J.
    University of Tsukuba.
    Morishita, N.
    Japan Atomic Energy Agency.
    Ohshima, T.
    University of Tsukuba.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Defects in low-energy electron-irradiated n-type 4H-SiC2010Ingår i: Physica Scripta, vol. T141, IOP Publishing , 2010, s. 014006-Konferensbidrag (Refereegranskat)
    Abstract [en]

    The bistable M-center, previously observed in high-energy proton-implanted 4H-SiC, was detected in low-energy electron-irradiated 4H-SiC using deep-level transient spectroscopy (DLTS). Irradiation increased the DLTS signals of the intrinsic defects Z(1/2) and EH6/7 and introduced the frequently observed defects EH1 and EH3. After the M-center is annealed out at about 650K without bias and at about 575K with bias applied to the sample during the annealing process, a new bistable defect in the low temperature range of the DLTS spectrum, the EB-center, evolves. Since low-energy irradiation affects mainly the carbon atoms in SiC, the M-center and the newly discovered EB-center are most probably carbon-related intrinsic defects.

  • 7.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, Junichi
    University of Tsukuba.
    Morishita, Norio
    Japan Atomic Energy Agency.
    Ohshima, Takeshi
    Japan Atomic Energy Agency.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Metastable defects in low-energy electron irradiated n-type 4H-SiC2010Ingår i: Materials Science Forum, Vols. 645-648, Trans Tech Publications , 2010, Vol. 645-648, s. 435-438Konferensbidrag (Refereegranskat)
    Abstract [en]

    After low-energy electron irradiation of epitaxial n-type 4H-SiC, the DUES peak amplitudes. of the defects Z(1/2) and EH6/7, which were already observed in as-grown layers, increased and the commonly found peaks EH1 and EH3 appeared. The bistable M-center, previously seen in high-energy proton implanted 4H-SiC, was detected. New bistable defects, the EB-centers, evolved after annealing out of the M-center, and EF3. The reconfiguration energies for one of the two EB-centers were determined to be about 0.96 eV for both transitions: from configuration I to II and from configuration II to I. Since low-energy electron irradiation (less than220 keV) affects mainly the carbon atom in SiC, both the M- and EB-centers are likely to be carbon related defects.

  • 8.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, Junichi
    Graduate School of Library, Information and Media Science, University of Tsukuba, 1-2 Kasuga,Tsukuba, Ibaraki 305-8850, Japan.
    Morishita, Norio
    Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
    Ohshima, Takeshi
    Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Observation of Bistable Defects in Electron Irradiated N-Type 4H-SiC2011Ingår i: Materials Science Forum Vols. 679-680 (2011) pp 249-252, Trans Tech Publications Inc., 2011, s. 249-252Konferensbidrag (Refereegranskat)
    Abstract [en]

    DLTS measurements show bistable behavior of the previously reported EH5 peak in low- and high-energy electron irradiation 4H-SiC. Both reconfiguration processes (A ! B and B ! A) take place above 700 ±C. By isothermal annealing, the reconfiguration rates were determined and the reconfiguration energy was calculated to EA = 2.4±0.2 eV. Since the defect is present already after low-energy electron irradiation, which mainly affects the C atom in SiC, the EH5 peak may be related to defects associated with C-vacancies or C-interstitials.

  • 9.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, J.
    University of Tsukuba.
    Morishita, N.
    Japan Atom Energy Agency.
    Ohshima, T.
    Japan Atom Energy Agency.
    Annealing behavior of the EB-centers and M-center in low-energy electron irradiated n-type 4H-SiC2011Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 109, nr 10, s. 103703-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    After low-energy electron irradiation of epitaxial n-type 4H-SiC with a dose of 5 x 10(16) cm(-2), the bistable M-center, previously reported in high-energy proton implanted 4H-SiC, is detected in the deep level transient spectroscopy (DLTS) spectrum. The annealing behavior of the M-center is confirmed, and an enhanced recombination process is suggested. The annihilation process is coincidental with the evolvement of the bistable EB-centers in the low temperature range of the DLTS spectrum. The annealing energy of the M-center is similar to the generation energy of the EB-centers, thus partial transformation of the M-center to the EB-centers is suggested. The EB-centers completely disappeared after annealing temperatures higher than 700 degrees C without the formation of new defects in the observed DLTS scanning range. The threshold energy for moving Si atom in SiC is higher than the applied irradiation energy, and the annihilation temperatures are relatively low, therefore the M-center, EH1 and EH3, as well as the EB-centers are attributed to defects related to the C atom in SiC, most probably to carbon interstitials and their complexes.

  • 10.
    Beyer, Franziska
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Deep levels in hetero-epitaxial as-grown 3C-SiC2010Ingår i: AIP Conference Proceedings, Vol. 1292, 2010, s. 63-66Konferensbidrag (Refereegranskat)
    Abstract [en]

    3C-SiC grown hetero-epitaxially on 4H- or 6H-SiC using a standard or a chloride-based CVD process were electrically characterized using IV, CV and DLTS. The reverse leakage current of the Au-Schottky diodes was  reduced to lower than 10-8 A at -2V by a thermal oxidation step using UV-light illumination at 200oC. The Schottky barrier height of the Ni and Au contacts were determined by IV measurement to be ØB = 0.575  eV and ØB = 0.593 eV, respectively, for a contact diameter of about 150 mm. One dominant DLTS peak was observed in the 3C-epilayers independently of the substrate at about EC0:60 eV which is attributed to W6-level in 3C-SiC. This deep level is thought to be related to an intrinsic defect.

  • 11.
    Beyer, Franziska
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Pedersen, Henrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Defects in 4H-SiC Layers Grown by Chloride-based Epitaxy2009Ingår i: Materials Science Forum Vols. 615-617 / [ed] Amador Pérez-Tomás, Trans Tech Publications , 2009, s. 373-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Chloride-based 4H-SiC epitaxial layers were investigated by DLTS, MCTS and PL. The DLTS spectra of the as grown samples showed dominance of the Z1/2 and the EH6/7 peaks. For growth rates exceeding 100 µm/h, an additional peak occurred in the DLTS spectra which can be assigned to the UT1 defect. The shallow and the deep boron complexes as well as the HS1 defect are observed in MCTS measurements. The PL spectra are completely dominated by the near band gap (NBG) emission. No luminescence from donor-acceptor pair occurred. The PL line related to the D1 centre was weakly observed. In the NBG region nitrogen bound exciton (N-BE) and free exciton (FE) related lines could be seen. The addition of chlorine in the growth process gives the advantage of high growth rates without the introduction of additional defects.

  • 12.
    Booker, Ian Don
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ul Hassan, Jawad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lilja, Louise
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Karhu, Robin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Bergman, J. Peder
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Danielsson, Örjan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Sveinbjörnsson, Einar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Carrier Lifetime Controlling Defects Z(1/2) and RB1 in Standard and Chlorinated Chemistry Grown 4H-SiC2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 8, s. 4104-4110Artikel i tidskrift (Refereegranskat)
    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.
    Carlsson, Patrick
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Son Tien, Nguyen
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Isoya, J
    University of Tsukuba.
    Morishita, N
    Japan Atom Energy Agency.
    Ohshima, T
    Japan Atom Energy Agency.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Deep levels in low-energy electron-irradiated 4H-SiC2009Ingår i: PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS, ISSN 1862-6254, Vol. 3, nr 4, s. 121-123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deep levels introduced by low-energy (200 keV) electron irradiation in n-type 4H-SiC epitaxial layers grown by chemical vapour deposition were studied by deep level transient spectroscopy (DLTS) and photoexcitation electron paramagnetic resonance (photo-EPR). After irradiation, several DLTS levels, EH1, EH3, Z(1/2), EH5 and EH6/7, often reported in irradiated 4H-SiC, were observed. In irradiated freestanding films from the same wafer, the EPR signals of the carbon vacancy in the positive and negative charge states, V-C(+) and V-C(-), respectively, can be observed simultaneously under illumination with light of certain photon energies. Comparing the ionization energies obtained from DLTS and photo-EPR, we suggest that the EH6/7 (at similar to E-C - 1.6 eV) and EH5 (at similar to E-C - 1.0 eV) electron traps may be related to the single donor (+ vertical bar 0) and the double acceptor (1- vertical bar 2-) level of V-C, respectively. Judging from the relative intensity of the DLTS signals, the EH6/7 level may also be contributed to by other unidentified defects.

  • 14.
    Gällström, Andreas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Magnusson, Björn
    Norstel AB, Norrköping, Sweden.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Gali, Adam
    Budapest University of Technology and Economics and Hungarian Academy of Science, Budapest, Hungary .
    Son, Nguyen Tien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ivanov, Ivan G.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Electronic Configuration of Tungsten in 4H-, 6H-, and 15R-SiC2012Ingår i: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, s. 211-216Konferensbidrag (Refereegranskat)
    Abstract [en]

    A commonly observed unidentified photoluminescence center in SiC is UD-1. In this report, the UD-1 center is identified to be tungsten related. The identification is based on (i) a W-doping study, the confirmation of W in the samples was made using deep level transient spectroscopy (DLTS), (ii) the optical activation energy of the absorption of UD-1 in weakly n-type samples corresponds to the activation energy of the deep tungsten center observed using DLTS. The tungsten-related optical centers are reported in 4H-, 6H-, and 15R-SiC. Further, a crystal field model for a tungsten atom occupying a Si-site is suggested. This crystal field model is in agreement with the experimental data available: polarization, temperature dependence and magnetic field splitting.

  • 15.
    Gällström, Andreas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Magnusson, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Gali, Adam
    Budapest University of Technology and Economics, Hungary.
    Son Tien, Nguyen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ivanov, Ivan Gueorguiev
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Optical identification and electronic configuration of tungsten in 4H-and 6H-SiC2012Ingår i: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, nr 10, s. 1462-1466Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several optically observed deep level defects in SiC are still unidentified and little is published on their behavior. One of the commonly observed deep level defects in semi-insulating SiC is UD-1. less thanbrgreater than less thanbrgreater thanThis report suggests that UD-1 is Tungsten related, based on a doping study and previously reported deep level transient spectroscopy data, as well as photo-induced absorption measurements. The electronic levels involved in the optical transitions of UD-1 are also deduced. The transitions observed in the photoluminescence of UD-1 are from a Gamma(C3v)(4), to two different final states, which transform according to Gamma(C3v)(5)circle plus Gamma(C3v)(6) and Gamma(C3v)(4), respectively.

  • 16.
    Gällström, Andreas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Magnusson, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Carlsson, Patrick
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Nguyen, Son Tien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Influence of Cooling Rate after High Temperature Annealing on Deep Levels in High-Purity Semi-Insulating 4H-SiC2007Ingår i: Materials Science Forum, vol. 556-557, Trans Tech Publications , 2007, s. 371-Konferensbidrag (Refereegranskat)
    Abstract [en]

    The influence of different cooling rates on deep levels in 4H-SiC after high temperature annealing has been investigated. The samples were heated from room temperature to 2300°C, followed by a 20 minutes anneal at this temperature. Different subsequent cooling sequences down to 1100°C were used. The samples have been investigated using photoluminescence (PL) and IV characteristics. The PL intensities of the silicon vacancy (VSi) and UD-2, were found to increase with a faster cooling rate.

  • 17. Hahn, S.
    et al.
    Beyer, Franziska
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Gällström, Andreas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Carlsson, Patrick
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Magnusson, Björn
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Niklas, J.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Contact-Less Electrical Defect Characterization of Semi-Insulating 6H-SiC Bulk Material2009Ingår i: Materials Science Forum Vols. 600-603, Trans Tech Publications , 2009, s. 405-408Konferensbidrag (Refereegranskat)
    Abstract [en]

    The novel technique microwave detected photo induced current transient spectroscopy (MD-PICTS) was applied to semi-insulating 6H-SiC in order to investigate the properties of inherent defect levels. Defect spectra can be obtained in the similar way to conventional PICTS and DLTS. However, there is no need for contacting the samples, which allows for non-destructive and spatially resolved electrical characterization. This work is focused on the investigation of semi-insulating 6H-SiC grown under different C/Si-ratios. In the corresponding MD-PICTS spectra several shallow defect levels appear in the low temperature range. However the peak assignment needs further investigation. Additionally different trap reemission dynamics are obtained for higher temperatures, which are supposed to be due to different compensation effects.

  • 18.
    Henry, Anne
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska C.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Andersson, Sven
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chloride based CVD of 3C-SiC on (0001) α-SiC substrates2011Ingår i: Materials Science Forum Vols. 679-680 (2011) pp 75-78, Trans Tech Publications Inc., 2011, s. 75-78Konferensbidrag (Refereegranskat)
    Abstract [en]

    A chloride-based chemical-vapor-deposition (CVD) process has been successfully used to grow very high quality 3C-SiC epitaxial layers on on-axis α-SiC substrates. An accurate process parameters study was performed testing the effect of temperature, surface preparation, precursor ratios, nitrogen addition, and substrate polytype and polarity. The 3C layers deposited showed to be largely single-domain material of very high purity and of excellent electrical characteristics. A growth rate of up to 10 μm/h and a low background doping enable deposition of epitaxial layers suitable for MOSFET devices.

  • 19.
    Henry, Anne
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Andersson, Sven
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    SiC epitaxy growth using chloride-based CVD2012Ingår i: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, nr 10, s. 1467-1471Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The growth of thick epitaxial SiC layers needed for high-voltage, high-power devices is investigated with the chloride-based chemical vapor deposition. High growth rates exceeding 100 mu m/h can be obtained, however to obtain device quality epilayers adjustments of the process parameters should be carried out appropriately for the chemistry used. Two different chemistry approaches are compared: addition of hydrogen chloride to the standard precursors or using methyltrichlorosilane, a molecule that contains silicon, carbon and chlorine. Optical and electrical techniques are used to characterize the layers.

  • 20.
    Henry, Anne
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    ul-Hassan, Jawad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Bergman, Peder
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Andersson, Sven
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Godignon, P.
    Thick epilayers for power devices2007Ingår i: Materials Science Forum, vol. 556-557, Trans Tech Publications , 2007, s. 47-Konferensbidrag (Refereegranskat)
    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.

  • 21.
    Kotamraju, Siva
    et al.
    Mississippi State University, USA .
    Krishnan, Bharat
    Mississippi State University, USA .
    Beyer, Franziska C.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Koshka, Yaroslav
    Mississippi State University, USA .
    Electrical and optical properties of high-purity epilayers grown by the low-temperature chloro-carbon growth method2012Ingår i: Materials Science Forum Vol 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, s. 129-132Konferensbidrag (Refereegranskat)
    Abstract [en]

    A reduced growth pressure (down to 10 Torr) was employed for the low-temperature chloro-carbon epitaxial growth. More than two times lower H-2 flow rate became possible. The optimal input H-2/Si and C/Si ratios were also lower. A significant reduction of the net free donor concentration resulted from the use of the low pressure, delivering partially compensated epilayers with the net free donor concentration below 7 x 10(13) cm(-3). Deep levels were characterized in the low-temperature epilayers for the first time. No Z(1/2) or EH6/7 centers could be detected by DLTS. No strong D-1 photoluminescence signature was observed. The high purity of the obtained epitaxial layers made it possible to use the low-temperature chloro-carbon epitaxial growth to fabricate drift regions of Schottky diodes for the first time. Promising values of the reverse breakdown voltage and the leakage current were obtained from the fabricated devices.

  • 22.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chloride-Based SiC Epitaxial Growth toward Low Temperature Bulk Growth2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 8, s. 3743-3751Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, chloride-based chemical vapor deposition (CVD) of SiC is used either to grow epitaxial layers at high growth rate and to facilitate homopolytypic growth on on-axis substrates or to grow bulk material at temperatures lower than 2000 °C. A vertical reactor configuration with an inlet of gas flow placed at the bottom of the reactor chamber and the exhaust at the top of it has been used. The chlorinated precursors have helped to eliminate or greatly reduce cluster formation, thereby allowing the deposition of thick SiC epilayers at growth rates exceeding 300 μm/h at 1700−1900 °C. Up to 1.5 mm thick homoepitaxial layers have been grown on up to 75 mm diameter 4H- or 6H-SiC wafers. Both on-axis and off-axis, Si-face and C-face polarities have been used. Our results show great promise for the realization of a high growth rate epitaxial process suitable for bulk growth at temperatures lower than those typically used. Such a process is interesting on account of the higher quality material and lower operating cost.

  • 23.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chloride-based CVD of 3C-SiC epitaxial layers on 6H(0001) SiC2010Ingår i: Physica Status Solidi (RRL) – Rapid Research Letters, ISSN 1862-6270, Vol. 4, nr 11, s. 305-307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The growth of 3C‐SiC epitaxial layers on nominally on‐axis 6H‐SiC Si‐face substrates using the chloride‐based CVD process is demonstrated. A hot‐wall CVD reactor was used and HCl was added to the standard precursors (silane and ethylene). Several growth parameters were tested: temperature, in‐situ surface preparation, C/Si ratio, Cl/Si ratio, and nitrogen addition. Each parameter had a very important effect on the polytype formation. In the case of 3C‐SiC deposition the morphology and typology of defects could change significantly depending on the different combinations of growth conditions, including the addition of nitrogen. At a growth rate of 10 μm/h, a mirror‐like surface with a single domain decorated by some parallel stripes and few epitaxial defects were obtained. The near‐band gap luminescence of high quality 3C‐SiC layers was characterized by very sharp lines. Microscope and AFM analysis showed a very smooth surface. A background doping in the low 1015 cm−3 range was achieved.

  • 24.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chloride-based CVD of 3C-SiC Epitaxial Layers on On-axis 6H (0001) SiC Substrates2010Ingår i: AIP Conference Proceedings, Vol. 1292, 2010, s. 7-10Konferensbidrag (Refereegranskat)
  • 25.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Andersson, Sven
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chlorinated precursor study in low temperature CVD of 4H-SiC2011Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, nr 10, s. 3074-3080Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low temperature chemical vapour deposition of SiC has gained interest in the last years for being less demanding in terms of reaction chamber lifetime, but also for allowing higher p-type dopant incorporation. Chloride-based CVD at low temperatures has been studied using chloromethane with tetrachlorosilane or silane, respectively and with or without controlled HCl addition. In this study we explore the use of methyltrichlorosilane (MTS) at growth temperatures significantly lower than what is commonly used for homoepitaxial growth of SiC. MTS is a molecule containing all the needed precursor atoms; its effects are compared to the standard CVD chemistry, consisting of silane, ethylene, and HCl.

    Very different chemistries between the two precursor systems are proposed; in the case of MTS, C/Si ratios higher than 1 were required, however using the standard chemistry ratios lower than 1 were needed to obtain a defect-free epitaxial layer. We also demonstrate the need of using Cl/Si ratios as high as 15 to achieve a growth rate of 13 μm/h for 8° off-axis 4H-SiC epitaxial layers at 1300 °C. Limitations due to the low growth temperature are discussed in light of the experimental evidence on the growth mechanism as determined by the morphology degradation and the limited growth rate. Finally a comparison between the epilayers morphology obtained on 4H-SiC substrates with different off-cuts are presented, confirming the importance of lower C/Si ratios for 4° off-axis material and the inevitable growth of the cubic SiC polytype on on-axis substrates.

  • 26.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Growth of smooth 4H-SiC epilayers on 4° off-axis substrates with chloride-based CVD at very high growth rate2011Ingår i: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 46, nr 8, s. 1272-1275Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    4H-SiC epilayers grown on 4º off-axis substrates at high rates usually suffer from step-bunching (very high surface roughness) or of extended triangular defects, both detrimental for device performance.

    In this study we developed a novel in situ pre-growth surface preparation based on hydrogen chloride (HCl) addition at a temperature higher than that used for the growth. This pre-growth etching procedure minimizes the density of triangular defects which usually occur at low temperatures and simultaneously enables growth at a temperature low enough to avoid stepbunching. Thanks to this surface preparation step, chloride-based CVD could be used for rapid epitaxial growth of high quality layers. In this study, layers were grown at rates of 100 μm/h yielding defect free epitaxial layers with very smooth surface (RMS value of 8.9 Å on 100x100 μm2 area).

  • 27.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    High growth rate of 4H-SiC epilayers grown on on-axis substrates with different chlorinated precursors2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 12, s. 5334-5340Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The epitaxial growth of 4H-SiC on on-axis substrates is a very important process to develop in order to accelerate the development and improve the performance of bipolar SiC based power devices, but until now, only relatively low growth rate processes have been demonstrated. The aim of this study is to demonstrate a high growth rate deposition process of high quality 4H-SiC epilayers on on-axis substrates, free of 3C-SiC inclusions. Previous studies showed that silicon-rich gas-phase conditions (prior to, and during the deposition process) and/or high Cl/Si ratios were vital in order to avoid 3C-SiC inclusions in the epitaxial layers when growing on on-axis substrates. This study combines the knowledge of surface pre-treatment with the chloride-based chemistry developed for off-axis growth. Two different precursor approaches were used, one adopting the standard precursors (silane and ethylene) with addition of hydrogen chloride (HCl), and the other based on the molecule methyltrichlorosilane (CH3SiCl3 or MTS). In this study we will show that using a MTS-based CVD process in combination with proper in situ silane etching and accurate optimisation of the other process parameters (temperature, C/Si and Cl/Si ratio) results in homoepitaxial growth of high purity and high quality 4H-SiC layers on on-axis Si-face substrates at a growth rate of 100 μm/h. Additionally, a higher efficiency of the MTS precursor chemistry was found and discussed.

  • 28.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lin, Yuan-Chih
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska C.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Andersson, Sven
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chloride-Based CVD at High Rates of 4H-SiC on On-Axis Si-Face Substrates2011Ingår i: Materials Science Forum Vols. 679-680 (2011) pp 59-62, Trans Tech Publications Inc., 2011, s. 59-62Konferensbidrag (Refereegranskat)
    Abstract [en]

    The epitaxial growth at 100 µm/h on on-axis 4H-SiC substrates is demonstrated in this study. Chloride-based CVD, which has been shown to be a reliable process to grow SiC epitaxial layers at rates above 100 µm/h on off-cut substrates, was combined with silane in-situ etching. A proper tuning of C/Si and Cl/Si ratios and the combination of different chlorinated precursors resulted in the homoepitaxial growth of 4H-SiC on Si-face substrates at high rates. Methyltrichlorosilane, added with silane, ethylene and hydrogen chloride were employed as precursors to perform epitaxial growths resulting in very low background doping concentration and high quality material, which could be employed for power devices structure on basal-plane-dislocation-free epitaxial layers.

  • 29.
    Leone, Stefano
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Andersson, Sven
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Canino, Andrea
    Consiglio Nazionale delle Ricerche IMM, Catania, Italy.
    La Via, Francesco
    Consiglio Nazionale delle Ricerche IMM, Catania, Italy.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chloride-Based CVD of 4H-SiC at High Growth Rates on Substrates with Different Off-Angles2012Ingår i: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, s. 113-116Konferensbidrag (Refereegranskat)
    Abstract [en]

    A review of recently achieved results with the chloride-based CVD on 8 degrees and 4 degrees off-axis and nominally on-axis 4H-SiC wafers is done to clarify the epitaxial growth mechanisms on different off-angle substrates. The process conditions selected for each off-axis angle become even more difficult when running at growth rates of 100 mu m/h or more. A fine-tuning of process parameters, mainly temperature, C/Si ratio and in situ surface preparation is necessary for each Wangle. Some trends related to the surface properties and the effective C/Si ratio existing on the surface prior to and during the epitaxial growth can be observed.

  • 30.
    Pedersen, Henrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Acceptor incorporation in SiC epilayers grown at high growth rate with chloride-based CVD2009Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 311, nr 13, s. 3364-3370Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A systematic p-type doping study has been performed on 4H- and 6H-SiC epilayers grown at high growth rate using chloride-based chemical vapor deposition. The effect of temperature, pressure, growth rate, C/Si-, Cl/Si ratio and dopant flow on the incorporation of the acceptor atoms aluminum and boron has been studied. The C/Si-ratio on the aluminum incorporation has similar behavior to what has been reported for the standard non-chlorinated low-growth rate process, while no clear effect of C/Si-ratio was observed for the boron incorporation. A higher Cl/Si-ratio seems to lead to lower aluminum and boron incorporation either due to more effective silicon supply at high Cl/Si ratio or due to removal of dopant atoms from the surface by chlorine. The doping concentration is stable to the variations in silicon molar fraction, growth pressure and growth temperature for the aluminum doped layers. Also p-type doping with gallium was tested.

  • 31.
    Pedersen, Henrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    ul-Hassan, Jawad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Donor incorporation in SiC epilayers grown at high growth rate with chloride-based CVD2009Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 311, nr 5, s. 1321-1327Artikel i tidskrift (Refereegranskat)
    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.

  • 32.
    Pedersen, Henrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Very high growth rate of 4H-SiC epilayers using the chlorinated precursor methyltrichlorosilane (MTS)2007Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 307, nr 2, s. 334-340Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall chemical vapour deposition (CVD) reactor with growth rates higher than 100 μm/h. The addition of chlorinated species to the gas mixture prevents silicon nucleation in the gas phase, thus allowing higher input flows of the precursors resulting in much higher growth rate than that of standard silicon carbide (SiC) epitaxial growth using only silane, SiH4, and hydrocarbons as precursors. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate, morphology, and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor. The growth rate dropped for C/Si<1 but was constant for C/Si>1. Further, the growth rate decreased with lower Cl/Si ratio. This study shows that MTS is a promising precursor for homoepitaxial growth of SiC within the concept of chloride-based SiC growth.

  • 33.
    Pedersen, Henrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Caracal Inc..
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Very high growth rate of 4H-SiC using MTS as chloride-based precursor2009Ingår i: Materials Science Forum, Vol. 600-603, Trans Tech Publications , 2009, Vol. 600-603, s. 115-118Konferensbidrag (Refereegranskat)
    Abstract [en]

    The chlorinated precursor methyltrichlorosilane (MTS), CH 3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si less than 1 but was constant for C/Si greater than 1. Further, the growth rate decreased with lower Cl/Si ratio.

  • 34.
    Pedersen, Henrik
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Leone, Stefano
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Beyer, Franziska
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Lundskog, Anders
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Chloride-based SiC epitaxial growth2009Ingår i: Materials Science Forum Vols. 615-617, Trans Tech Publications , 2009, s. 89-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Some aspects of the chloride-based CVD growth process have been investigated by using both the approach to add HCl to the standard precursors or/and by using the single molecule precursor methyltrichlorosilane (MTS). The efficiency of the process for different precursors, the growth rate stability and the effect that the Cl/Si-ratio has on the growth have been studied. MTS is showed to be the most efficient precursor; the growth can be hindered by to much chlorine in the gas mixture. The Cl/Si-ratio is also found to be a process parameter that affects the amount of incorporated nitrogen in the epilayers.

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