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  • 1.
    Ariyawong, Kanaparin
    et al.
    Laboratoire des Matériaux et du Génie Physique, Grenoble INP – CNRS, France.
    Jokubavicius, Valdas
    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.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Step Instability in Sublimation Epitaxy on Low Off-Axis 6H-SiC2013Conference paper (Refereed)
  • 2.
    Asghar, M.
    et al.
    Islamia University of Bahawalpur, Pakistan .
    Iqbal, F.
    Islamia University of Bahawalpur, Pakistan .
    Faraz, Sadia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wahab, Qamar
    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.
    Characterization of deep level defects in sublimation grown p-type 6H-SiC epilayers by deep level transient spectroscopy2012Conference paper (Refereed)
    Abstract [en]

    In this study deep level transient spectroscopy has been performed on boron-nitrogen co-doped 6H-SiC epilayers exhibiting p-type conductivity with free carrier concentration (N-A-N-D)similar to 3 x 10(17) cm(-3). We observed a hole H-1 majority carrier and an electron E-1 minority carrier traps in the device having activation energies E-nu + 0.24 eV, E-c -0.41 eV, respectively. The capture cross-section and trap concentration of H-1 and E-1 levels were found to be (5 x 10(-19) cm(2), 2 x 10(15) cm(-3)) and (1.6 x 10(-16) cm(2), 3 x 10(15) cm(-3)), respectively. Owing to the background involvement of aluminum in growth reactor and comparison of the obtained data with the literature, the H-1 defect was identified as aluminum acceptor. A reasonable justification has been given to correlate the E-1 defect to a nitrogen donor.

  • 3.
    Asghar, M.
    et al.
    Islamia University of Bahawalpur, Pakistan .
    Iqbal, F.
    Islamia University of Bahawalpur, Pakistan .
    Faraz, Sadia Municha
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wahab, Qamar
    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.
    Study of deep level defects in doped and semi-insulating n-6H-SiC epilayers grown by sublimation method2012Conference paper (Refereed)
    Abstract [en]

    Deep level transient spectroscopy (DLTS) is employed to study deep level defects in n-6H-SiC (silicon carbide) epilayers grown by the sublimation method. To study the deep level defects in n-6H-SiC, we used as-grown, nitrogen doped and nitrogen-boron co-doped samples represented as ELS-1, ELS-11 and ELS-131 having net (N-D-N-A) similar to 2.0 x 10(12) cm(-3), 2 x 10(16) cm(-3) and 9 x 10(15) cm(3), respectively. The DLTS measurements performed on ELS-1 and ELS-11 samples revealed three electron trap defects (A, B and C) having activation energies E-c - 0.39 eV, E-c - 0.67 eV and E-c - 0.91 eV, respectively. While DLTS spectra due to sample ELS-131 displayed only A level. This observation indicates that levels B and C in ELS-131 are compensated by boron and/or nitrogen-boron complex. A comparison with the published data revealed A, B and C to be E-1/E-2, Z(1)/Z(2) and R levels, respectively.

  • 4.
    Beshkova, Milena
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    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.
    Sublimation epitaxy of 3C-SiC grown at Si- and C-rich conditions2012In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 86, no 10, p. 1595-1599Article in journal (Refereed)
    Abstract [en]

    3C-SiC layers have been grown by using sublimation epitaxy at a source temperature of 2000 degrees C, under vacuum conditions (andlt;10(-5) mbar) on well oriented (on-axis) 6H-SiC (0001) substrates. Close space sublimation growth geometry has been used in a RF-heated furnace employing high-purity graphite crucible with a possibility to change the growth environment from Si vapor-rich to C vapor-rich. The optical microscopy in transmission mode reveals continuous 3C-domains for 3C-SiC with less than 0.4% 6H-inclusions for the layer grown at Si-rich conditions, and separate 3C-SiC domains for the layer grown at C-rich conditions. The type of 6H-inclusions for layers with continuous domain structure investigated by Atomic Force Microscopy (AFM) is discussed. 2Theta-omega scan shows 0006 and 111 peaks coming from the substrate and the layer, respectively with a higher intensity of the 111 peak for 3C-SiC grown at Si-rich conditions which is related with the continuous character of the 3C-SiC domains.

  • 5.
    Beshkova, Milena
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lorenzzi, J.
    UMR-CNRS.
    Jegenyes, N.
    UMR-CNRS.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ferro, G.
    UMR-CNRS.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Properties of 3C-SiC Grown by Sublimation Epitaxy on Different Type of Substrates2010In: Materials Science Forum, Vols. 645-648, Transtec Publications; 1999 , 2010, Vol. 645-648, p. 183-186Conference paper (Refereed)
    Abstract [en]

    3C-SiC layers have been grown by using sublimation epitaxy at a temperature of 2000 degrees C, on different types of on-axis 6H-SiC(0001) substrates. The influence of the type of substrate on the morphology of the layers investigated by Atomic Force Microscopy (AFM) is discussed. Stacking faults are studied by reciprocal space map (RSM) which shows that double positions domains exists.

  • 6.
    Beshkova, Milena
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Vasiliauskas, Remigijus
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Properties of 3C-SiC Grown by Sublimation Epitaxy2009In: ECSCRM2008,2008, 2009Conference paper (Refereed)
    Abstract [en]

      

  • 7.
    Beshkova, Milena
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Vasiliauskas, Remigijus
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Structural Properties of 3C-SiC Grown by Sublimation Epitaxy2009In: ECSCRM2009,2009, Materials Science Forum Vols. 615-617: Trans Tech Publications , 2009, p. 181-184Conference paper (Refereed)
    Abstract [en]

    The present paper deals with morphological and structural investigation of 3C-SiC layers grown by sublimation epitaxy on on axis 6H-SiC(0001) at source temperature 2000 °C, under vacuum conditions (<10-5 mbar) and different temperature gradients in the range of 5-8 °C/mm. The layer grown at a temperature gradient 6 °C/mm has the largest average domain size of 0.4 mm2 assessed by optical microscope in transmission mode. The rocking curve full width at half maximum (FWHM) of (111) reflection is 43 arcsec which suggests good crystalline quality. The AFM image of the same layer shows steps with height 0.25 nm and 0.75 nm which are characteristic of a stacking fault free 3C-SiC surface and c-axis repeat height, respectively.

  • 8. Bikbajevas, V
    et al.
    Grivickas, V
    Stolzer, M
    Velmre, E
    Udal, A
    Grivickas, P
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Impact of phonon drag effect on Seebeck coefficient in p-6H-SiC: Experiment and simulation2003In: Materials Science Forum, Vols. 433-436, 2003, Vol. 433-4, p. 407-410Conference paper (Refereed)
    Abstract [en]

    The temperature dependence of Seebeck coefficient (S) for p-6H-SiC has been obtained. It increases from 2 up to 5.2 mV/K when temperature decreases from 400 down to 240 K. It is shown that phonon drag effect makes critical contribution to the S value. Improved theoretical model involving 4-phonon scattering process has been proposed for the simulation of Seebeck coefficient phonon pail.

  • 9.
    Bladh, Mats
    et al.
    Linköping University, Department of Thematic Studies, Technology and Social Change. Linköping University, Faculty of Arts and Sciences.
    Syväjärvi, MikaelLinköping University, The Institute of Technology. Linköping University, Department of Thematic Studies. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    New Lighting—New LEDs: Aspects on light-emitting diodes from social and material science perspectives2010Collection (editor) (Other academic)
    Abstract [en]

    The papers published in this volume were presented at Sveriges Energiting 2010 (The Swedish Energy Parliament 2010) in Älvsjö south of Stockholm in March 16-17. Sveriges Energiting is Sweden’s largest scene for discussion of energy and climate related activities. It gathered about 2300 participants and had a broad range of energy related issues covered, such as transport, future energy systems, industrial energy, energy and climate, energy efficiency and many more, including several on lighting. One session was initiated and organized by me: “New Lighting—New LEDs”.

    I hope this kind of cooperation between lighting researchers will continue in the future. One step in this direction is Nordic Light Emitting Diode Initiative (NORLED), initiated by Professor Mikael Syväjärvi, Linköping University. The aim of the NORLED project is to develop an innovative and industrially feasible white LED technology for general lighting. The project consortium is composed of partners from Sweden, Denmark, Germany and Norway.

    Linköping, September 2010

    Mats Bladh

  • 10.
    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.
    Kakanakova-Georgieva, Anelia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Effect of boron on the resistivity of compensated 4H-SiC2003In: Journal of electronic materials, ISSN 0361-5235, Vol. 32, no 5, p. 452-457Article in journal (Refereed)
    Abstract [en]

    High-resistivity 4H-SiC samples grown by sublimation with a high growth rate are studied. The measurements show resistivity values up to a high of 104 Ωcm. The secondary ion mass spectroscopy (SIMS) results revealed a presence of only common trace impurities such as nitrogen, aluminum, and boron. To understand the compensation mechanism in these samples, capacitance deep-level transient spectroscopy (DLTS) on the p-type epilayers has been performed. By correlation between the growth conditions and SIMS results, we apply a model in which it is proposed that an isolated carbon vacancy donorlike level is a possible candidate responsible for compensation of the shallow acceptors in p-type 4H-SiC. A relation between cathodoluminescence (CL) and DLTS data is taken into account to support the model.

  • 11.
    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.
    Porro, Samuele
    Polytechnic of Turin, Physics Department, Torino, Italy.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Evaluation of On-state Resistance and Boron-related Levels in n-type 4H-SiC2005In: Materials Science Forum, Vols. 483-485, 2005, Vol. 483-485, p. 425-428Conference paper (Refereed)
    Abstract [en]

    Specific on-resistance Ron estimated from current density-voltage characteristics of Schottky diodes on thick layers exhibits variations from tens of mΩ.cm2 to tens of Ω.cm2 for different doping levels. In order to understand the occurrence of high on-state resistance, Schottky barrier heights were first estimated for both forward and reverse bias with the application of thermionic emission theory and were in agreement with a literature reported values. Decrease in mobility with the temperature was observed and its dependencies of T–1.3 and T–2.0 for moderately doped and low doped samples respectively were estimated. From deep level measurements by Minority Carrier Transient Spectroscopy, an influence of shallow boron related levels and D-center on dependence of on-state resistance was observed, being more pronounced in low doped samples. Similar tendency was observed in depth profiling of Ron. This suggests a major role of boron in a compensation mechanism thus resulting in high Ron.

  • 12.
    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.

  • 13.
    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. Linköping University, The Institute of Technology.
    Wahab, Qamar Ul
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Evaluation of MOS structures processed on 4H–SiC layers grown by PVT epitaxy2005In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 49, no 12, p. 1917-1920Article in journal (Refereed)
    Abstract [en]

    MOS capacitors have been fabricated on 4H–SiC epilayers grown by physical vapor transport (PVT) epitaxy. The properties were compared with those on similar structures based on chemical vapor deposition (CVD) layers. Capacitance–voltage (CV) and conductance measurements (GV) were performed in the frequency range of 1 kHz to 1 MHz and also at temperatures up to 475 K. Detailed investigations of the PVT structures indicate a stable behaviour of the interface traps from room temperature up to 475 K. The amount of positive oxide charge QO is 6.83 × 109 cm−2 at room temperature and decreases with temperature increase. This suggests that the processed devices are temperature stable. The density of interface states Dit obtained by Nicollian–Brews conductance method is lower in the structure based on the PVT grown sample.

  • 14.
    Ciechonski, Rafal
    et al.
    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.
    Syväjärvi, Mikael
    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.
    Effect of Ambient on 4H-SiC Bulk Crystals grown by Sublimation2003In: Materials Science Forum, Vols. 433-436 / [ed] Peder Bergman and Erik Janzén, 2003, Vol. 433-436, p. 75-78Conference paper (Refereed)
    Abstract [en]

    Sublimation bulk growth in vacuum using graphite crucibles and such with tantalum shielding of the crucible walls has been studied. Residual nitrogen, aluminum and boron doping in the material grown in vacuum is presented. Activation energies of growth rate in respect to growth temperature in vacuum are deduced. The estimated values are 21 kcallmole for growth temperatures below 2075°C and 128 kcal/mole in the range of growth temperatures between 2075°C and 2275°C. Cathodoluminescence spectra taken from samples grown in the graphite crucible in absence of tantalum under different pressures show nitrogen-alurninum DAP transition and strong luminescence from deep boron. This is not the case for samples grown in the tantalum environment.

  • 15. Dannefaer, S.
    et al.
    Avalos, V.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    The role of nitrogen in the annealing of vacancies in 4H-SiC2005In: Materials Science Forum, Vols. 483-485, 2005, Vol. 483-485, p. 481-484Conference paper (Refereed)
  • 16. Dannefaer, S
    et al.
    Avalos, V
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Vacancies in As-grown and electron-irradiated 4H-SiC epilayers investigated by positron annihilation2003In: Materials Science Forum, Vols. 433-436, 2003, Vol. 433-4, p. 173-176Conference paper (Refereed)
    Abstract [en]

    Epilayers of 4H-SiC were investigated by positron annihilation spectroscopies: four epilayers and their substrates were investigated. The epilayers (47 to 220 mum thick) contained significantly lower grown-in vacancy concentration than did their substrates, and there was no dependency on layer thickness. Upon electron irradiation silicon vacancies were introduced at the same rate in epilayer and in substrate.

  • 17. Davydov, SY
    et al.
    Savkina, NS
    Lebedev, Alexander
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Simple model for calculation of SiC epitaxial layers growth rate in vacuum.2004In: Materials Science Forum, Vols. 457-460, 2004, Vol. 457-460, p. 249-252Conference paper (Refereed)
    Abstract [en]

    Within the frame of a simple model, based on Hertz-Knudsen equation with account of temperature dependant sticking coefficient, temperature dependence of silicon carbide epitaxial layers growth rate in vacuum has been calculated. Calculation results are in a good agreement with the experimental data.

  • 18.
    Davydov, S.Yu.
    et al.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, Politekhnicheskaya ul. 26, St. Petersburg 194021, Russian Federation.
    Lebedev, A.A.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, Politekhnicheskaya ul. 26, St. Petersburg 194021, Russian Federation.
    Savkina, N.S.
    Ioffe Physicotechnical Institute, Russian Academy of Sciences, Politekhnicheskaya ul. 26, St. Petersburg 194021, Russian Federation.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A Simple Model for Calculating the Growth Rate of Epitaxial Layers of Silicon Carbide in Vacuum2004In: Semiconductors (Woodbury, N.Y.), ISSN 1063-7826, E-ISSN 1090-6479, Vol. 38, no 2, p. 150-152Article in journal (Refereed)
    Abstract [en]

    The temperature dependence of the growth rate of epitaxial layers of silicon carbide in vacuum was calculated within the simple model based on the Hertz-Knudsen equation, taking into account the temperature-dependent sticking coefficient. The calculation results fit the experimental data well. © 2004 MAIK "Nauka/Interperiodica".

  • 19.
    Eriksson, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Pearce, Ruth
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Iakimov, Tihomir
    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.
    Gogova, Daniela
    Leibniz Institute of Crystal Growth, Berlin, Germany .
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    The influence of substrate morphology on thickness uniformity and unintentional doping of epitaxial graphene on SiC2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, no 24, p. 241607-Article in journal (Refereed)
    Abstract [en]

    A pivotal issue for the fabrication of electronic devices on epitaxial graphene on SiC is controlling the number of layers and reducing localized thickness inhomogeneities. Of equal importance is to understand what governs the unintentional doping of the graphene from the substrate. The influence of substrate surface topography on these two issues was studied by work function measurements and local surface potential mapping. The carrier concentration and the uniformity of epitaxial graphene samples grown under identical conditions and on substrates of nominally identical orientation were both found to depend strongly on the terrace width of the SiC substrate after growth.

  • 20. Ewing, D.J.
    et al.
    Porter, L.M.
    Wahab, Qamar Ul
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Ciechonski, Rafal
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Inhomogeneous electrical characteristics in 4H-SiC Schottky diodes2007In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 22, no 12, p. 1287-1291Article in journal (Refereed)
    Abstract [en]

    Hundreds of current-voltage (I-V) measurements of Ni, Pt and Ti Schottky diodes on 4H-SiC were conducted at low applied voltages. The SiC substrates contained homoepitaxial layers grown by either chemical vapor deposition or sublimation. While near-ideal contacts were fabricated on all samples, a significant percentage of diodes (∼7%-50% depending on the epitaxial growth method and the diode size) displayed a non-ideal, or inhomogeneous, barrier height. These 'non-ideal' diodes occurred regardless of growth technique, pre-deposition cleaning method, or contact metal. In concurrence with our earlier reports in which the non-ideal diodes were modeled as two Schottky barriers in parallel, the lower of the two Schottky barriers, when present, was predominantly centered at one of the three values: ∼0.60, 0.85 or 1.05 eV. The sources of these non-idealities were investigated using electron-beam- induced current (EBIC) and deep-level transient spectroscopy (DLTS) to determine the nature and energy levels of the defects. DLTS revealed a defect level that corresponds with the low- (non-ideal) barrier height, at ∼0.60 eV. It was also observed that the I-V characteristics tended to degrade with increasing deep-level concentration and that inhomogeneous diodes tended to contain defect clusters. Based on the results, it is proposed that inhomogeneities, in the form of one or more low-barrier height regions within a high-barrier height diode, are caused by defect clusters that locally pin the Fermi level. © 2007 IOP Publishing Ltd.

  • 21.
    Gavryushin, V.
    et al.
    Institute of Applied Research, Vilnius University, Lithuania .
    Gulbinas, K
    Institute of Applied Research, Vilnius University, Lithuania .
    Grivickas, V.
    Institute of Applied Research, Vilnius University, Lithuania .
    Karaliunas, M.
    Institute of Applied Research, Vilnius University, Lithuania .
    Stasiūpnas, M.
    Institute of Applied Research, Vilnius University, Lithuania .
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    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.
    Examination of Photoluminescence Temperature Dependencies in N-B Co-doped 6H-SiC2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012003-Article in journal (Refereed)
    Abstract [en]

    Two overlapping photoluminescent (PL) bands with a peaks (half-width) at 1.95 eV (0.45 eV) and 2.15 eV (0.25 eV), correspondingly at 300 K, are observed in heavily B-N co-doped 6H-SiC epilayers under high-level excitation condition. The low energy band dominates at low temperatures and decreases towards 300 K which is assigned to DAP emission from the nitrogen trap to the deep boron (dB) with phonon-assistance. The 2.15 eV band slightly increases with temperature and becomes comparable with the former one at 300 K. We present a modelling comprising electron de-trapping from the N-trap, i.e. calculating trapping and de-trapping probabilities. The T-dependence of the 2.15 eV band can be explained by free electron emission from the conduction band into the dB center provided by similar phonon-assistance

  • 22. Glans, P.-A.
    et al.
    Balasubramanian, T.
    MAX-Lab, Lund University, S-221 00, Lund, Sweden.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Johansson, Leif
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Core level and valence band photoemission study of the (1 1 1) and (1¯ 1¯ 1¯) surfaces of 3C-SiC2001In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 470, no 3, p. 284-292Article in journal (Refereed)
    Abstract [en]

    A core level and valence band photoemission study of thick 3C-SiC(1 1 1) and 3C-SiC(1¯ 1¯ 1¯) epilayers grown by sublimation epitaxy is reported. The as introduced samples show threefold 1×1 low-energy electron diffraction patterns. For the Si face v3 and 6v3 reconstructed surfaces develop after in situ heating to 1100 °C and 1300 °C, respectively. For the C face a 3×3 reconstruction form after heating to 980 °C. A semiconducting behavior is observed for the v3 and 3×3 reconstructed surfaces while the 6v3 reconstruction show a Fermi edge and thus a metallic-like behavior. The surface state on the v3 surface is investigated and found to have ?1 symmetry and a total band width of 0.10 eV within the first surface Brillouin zone. For the Si2p and C 1s core levels binding energies and surface shifted components are extracted and compared to earlier reported results for 6H- and 4H-SiC.

  • 23.
    Grivickas, P.
    et al.
    Dept. of Solid State Electronics, Roy. Inst. Technol., E., Kista-Stockholm, Sweden.
    Galeckas, A.
    Dept. of Solid State Electronics, Roy. Inst. Technol., E., Kista-Stockholm, Sweden.
    Linnros, J.
    Dept. of Solid State Electronics, Roy. Inst. Technol., E., Kista-Stockholm, Sweden.
    Syväjärvi, Mikael
    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.
    Grivickas, V.
    Inst. of Mat. Sci. and Appl. Res., Vilnius Univ., Sauletekio 10, 2054, Vilnius, Lithuania.
    Tellefsen, J.A.
    Department of Physics II, Roy. Inst. of Technology, S-100 44, Stockholm, Sweden.
    Carrier lifetime investigation in 4H-SiC grown by CVD and sublimation epitaxy2001In: Materials Science in Semiconductor Processing, Vol. 4, 2001, Vol. 4, no 1-3, p. 191-194Conference paper (Refereed)
    Abstract [en]

    Depth-resolved carrier lifetime measurements were performed in low-doped epitaxial layers of 4H silicon carbide samples. The technique used was a pump-and-probe technique where carriers are excited by an above-bandgap laser pulse and probed by free carrier absorption. Results from chemical vapour deposition samples show that lifetimes as high as 2 µs may be observed in the mid-region of 40 µm thick epilayers. For epilayers grown by the sublimation method decay transients were characterized by a fast (few nanoseconds) initial recombination, tentatively assigned to the `true' lifetime, whereas a slow tail of several hundred microsecond decay time was assigned to trapping centres. From the saturation of this level at increased pumping we could derive the trapping concentration and their depth distribution peaking at the epilayer/substrate interface.

  • 24.
    Grivickas, V.
    et al.
    Institute of Applied Research, Vilnius University, Lithuania .
    Gulbinas, K
    Institute of Applied Research, Vilnius University, Lithuania .
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Karaliunas, M.
    Institute of Applied Research, Vilnius University, Lithuania.
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan .
    Linnarsson, Margareta
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Carrier Lifetimes and Influence of In-Grown Defects in N-B Co-Doped 6H-SiC2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012004-Article in journal (Refereed)
    Abstract [en]

    The thick N-B co-doped epilayers were grown by the fast sublimation growth method and the depth-resolved carrier lifetimes have been investigated by means of the free-carrier absorption (FCA) decay under perpendicular probe-pump measurement geometry. In some samples, we optically reveal in-grown carbon inclusions and polycrystalline defects of substantial concentration and show that these defects slow down excess carrier lifetime and prevent donor-acceptor pair photo luminescence (DAP PL). A pronounced electron lifetime reduction when injection level approaches the doping level was observed. It is caused by diffusion driven non-radiative recombination. However, the influence of surface recombination is small and insignificant at 300 K.

  • 25.
    Grivickas, V
    et al.
    Vilnius State Univ, Inst Mat Res & Appl Sci, LT-2054 Vilnius, Lithuania Univ Halle Wittenberg, FB Phys, DE-06120 Halle, Germany Tallinn Tech Univ, Inst Elect, EE-19086 Tallinn, Estonia Royal Inst Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Stolzer, M
    Vilnius State Univ, Inst Mat Res & Appl Sci, LT-2054 Vilnius, Lithuania Univ Halle Wittenberg, FB Phys, DE-06120 Halle, Germany Tallinn Tech Univ, Inst Elect, EE-19086 Tallinn, Estonia Royal Inst Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Velmre, E
    Vilnius State Univ, Inst Mat Res & Appl Sci, LT-2054 Vilnius, Lithuania Univ Halle Wittenberg, FB Phys, DE-06120 Halle, Germany Tallinn Tech Univ, Inst Elect, EE-19086 Tallinn, Estonia Royal Inst Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Udal, A
    Vilnius State Univ, Inst Mat Res & Appl Sci, LT-2054 Vilnius, Lithuania Univ Halle Wittenberg, FB Phys, DE-06120 Halle, Germany Tallinn Tech Univ, Inst Elect, EE-19086 Tallinn, Estonia Royal Inst Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Grivickas, P
    Vilnius State Univ, Inst Mat Res & Appl Sci, LT-2054 Vilnius, Lithuania Univ Halle Wittenberg, FB Phys, DE-06120 Halle, Germany Tallinn Tech Univ, Inst Elect, EE-19086 Tallinn, Estonia Royal Inst Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Bikbajevas, V
    Vilnius State Univ, Inst Mat Res & Appl Sci, LT-2054 Vilnius, Lithuania Univ Halle Wittenberg, FB Phys, DE-06120 Halle, Germany Tallinn Tech Univ, Inst Elect, EE-19086 Tallinn, Estonia Royal Inst Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Thermopower measurements in 4H-SiC and theoretical calculations considering the phonon drag effect2001In: Materials Science Forum, Vols. 353-356, 2001, Vol. 353-3, p. 491-494Conference paper (Refereed)
    Abstract [en]

    The Seebeck coefficient study in a heavily nitrogen-doped n-type 4H-SiC epilayer in the direction perpendicular to c-axis is presented. The Seebeck coefficient steeply increases from 0.56 mV/K to 1.7 mV/K with decreasing temperature in the range 400-80 R. This behavior is explained by the phonon drag effect. An approach to the theoretical modeling of the phonon drag effect is discussed and simulation of the Seebeck coefficient temperature-dependence is displayed.

  • 26.
    Gulbinas, Karolis
    et al.
    Vilnius University, Lithuania .
    Ščajev, P,
    Vilnius University, Lithuania .
    Bikbajavas, V.
    Vilnius University, Lithuania .
    Grivickas, V.
    Vilnius University, Lithuania .
    Korolik, O.V.
    Belarusian State University, Minsk, Belarus .
    Mazanik, A.V
    Belarusian State University, Minsk, Belarus .
    Fedotov, A.K.
    Belarusian State University, Minsk, Belarus .
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Linnarsson, Margareta
    Royal Institute of Technology, Kista, Sweden .
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan .
    Raman Scattering and Carrier Diffusion Study in Heavily Co-doped 6H-SiC Layers2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012005-Article in journal (Refereed)
    Abstract [en]

    Thick 6H-SiC epilayers were grown using the fast sublimation method on low-off-axis substrates. They were co-doped with N and B impurities of ≈1019 cm−3 and (41016–51018) cm−3 concentration, respectively. The epilayers exhibited donor-acceptor pair (DAP) photoluminescence. The micro-Raman spectroscopic study exposed a compensated n-6H-SiC epilayer of common quality with some 3C-SiC inclusions. The compensation ratio of B through 200 μm thick epilayer varied in 20-30% range. The free carrier diffusivity was studied by transient grating technique at high injection level. The determined ambipolar diffusion coefficient at RT was found to decrease from 1.15 cm2/s to virtually 0 cm2/s with boron concentration increasing by two orders.

  • 27.
    Gällström, Andreas
    et al.
    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.
    Carlsson, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Nguyen, Son Tien
    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.
    Beyer, Franziska
    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.
    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.
    Influence of Cooling Rate after High Temperature Annealing on Deep Levels in High-Purity Semi-Insulating 4H-SiC2007In: Materials Science Forum, vol. 556-557, Trans Tech Publications , 2007, p. 371-Conference paper (Refereed)
    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.

  • 28.
    Henry, Anne
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Magnusson, Björn
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Linnarsson, MK
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Solid State Elect, SE-16440 Kista, Sweden Okmet AB, SE-58330 Linkoping, Sweden.
    Ellison, A
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Solid State Elect, SE-16440 Kista, Sweden Okmet AB, SE-58330 Linkoping, Sweden.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Yakimova, Rositsa
    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.
    Presence of hydrogen in SiC2001In: Materials Science Forum, Vols. 353-356, 2001, Vol. 353-3, p. 373-376Conference paper (Refereed)
    Abstract [en]

    An unexpected presence of hydrogen in 4H-SiC was revealed by the observation of hydrogen related lines in the low-temperature photoluminescence (LTPL) spectrum after secondary ion mass spectrometry (SIMS) measurements. The lines were not observed before SIMS. The high-energy ions during SIMS are proposed to break the boron-hydrogen bonds. This phenomenon is observable only for a certain impurity concentration in the material due to the competition of various recombination channels during the LTPL experiment.

  • 29.
    Hens, Philip
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    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.
    Wagner, G
    Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, D-12489 Berlin, Germany.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, P
    Materials for Electronics and Energy Technology, University Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sublimation growth of thick freestanding 3C-SiC using CVD-templates on silicon as seeds2012In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 67, no 1, p. 300-302Article in journal (Refereed)
    Abstract [en]

    Cubic silicon carbide is a promising material for medium power electronics operating at high frequencies and for the subsequent growth of gallium nitride for more efficient light emitting diodes. We present a new approach to produce freestanding cubic silicon carbide (3C-SiC) with the ability to obtain good crystalline quality regarding increased domain size and reduced defect density. This would pave the way to achieve substrates of 3C-SiC so that the applications of cubic silicon carbide material having selectively (111) or (001) oriented surfaces can be explored. Our method is based on the combination of the chemical vapor deposition method and the fast sublimation growth process. Thin layers of cubic silicon carbide grown heteroepitaxially on silicon substrates are for the first time used for a subsequent sublimation growth step to increase layer thicknesses. We have been able to realize growth of freestanding (001) oriented 3C-SiC substrates using growth rates around 120 μm/h and diameters of more than 10 mm. The structural quality from XRD rocking curve measurements of (001) oriented layers shows good FWHM values down to 78 arcsec measured over an area of 1 × 2 mm2, which is a quality improvement of 2–3 times compared with other methods like CVD.

  • 30.
    Hens, Philip
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Müller, J.
    University of Erlangen-Nürnberg, Germany.
    Wagner, G.
    Leibniz Institute for Crystal Growth, Berlin, Germany.
    Liljedahl, Rickard
    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.
    Spiecker, E.
    University of Erlangen-Nürnberg, Germany.
    Wellmann, P.
    University of Erlangen-Nuremberg, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Freestanding 3C-SiC grown by sublimation epitaxy using 3C-SiC templates on silicon2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 177-180Conference paper (Refereed)
    Abstract [en]

    In this work a new approach for the production of freestanding cubic silicon carbide (3C-SiC) in (001) orientation is presented which is based on the combination of chemical vapor deposition (CVD) and the fast sublimation growth process (FSGP). Fast homoepitaxial growth of 3C-SiC using sublimation epitaxy on a template created by CVD growth on silicon substrates allows to obtain thick freestanding material with low defect densities. Using standard silicon wafers as substrate material permits a cost efficient process and the applying of wafers with different orientations. The (001) orientation used in this work will potentially allow further heteroepitaxial growth of other cubic semiconductors, like e.g. gallium nitride (GaN).

  • 31.
    Hens, Philip
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Müller, Julian
    University of Erlangen-Nuremberg, Erlangen, Germany.
    Wagner, Günter
    Leibniz Institute for Crystal Growth, Berlin, Germany.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Spiecker, Erdman
    University of Erlangen-Nuremberg, Erlangen, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Defect generation and annihilation in 3C-SiC-(001) homoepitaxial growth by sublimation2013In: Silicon Carbide and Related Materials 2012 / [ed] Alexander A. Lebedev, Sergey Yu. Davydov, Pavel A. Ivanov and Mikhail E. Levinshtein, Trans Tech Publications , 2013, Vol. 740-742, p. 283-286Conference paper (Refereed)
    Abstract [en]

    In this paper we present an investigation on the defect generation and annihilation during the homoepitaxial growth step of cubic silicon carbide by sublimation epitaxy on templates grown by chemical vapor deposition on silicon substrates. Several structural defects like stacking faults, twins and star-defects show opposite evolution from the template layer into the sublimation grown material. While single planar defects tend to annihilate with increasing layer thickness, the defect clusters assigned to the star-defects are enlarging. These issues contribute to a balance of how to achieve the best possible quality on thick layers.

  • 32.
    Hens, Philip
    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.
    Oehlschläger, F.
    Wellman, P.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    P- and n-type doping in SiC sublimation epitaxy using highly doped substrates2009In: ECSCRM2008,2008, Materials Science Forum Vols. 615-617: Trans Tech Publications , 2009, p. 85-88Conference paper (Refereed)
    Abstract [en]

    The co-doping of nitrogen and aluminum has been studied in the sublimation epitaxy growth process. It is shown that the doping may be tuned from n-type to p-type by effect of substrate doping, growth face and volume of the growth crucible. The co-doped layers show a nearly ideal I V characteristic and luminescence at room temperature.

  • 33.
    Hens, Philip
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology. University of Marburg, Germany.
    Zakharov, Alexei A.
    Lund University, Sweden.
    Iakimov, Tihomir
    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.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Large area buffer-free graphene on non-polar (001) cubic silicon carbide2014In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 80, p. 823-829Article in journal (Refereed)
    Abstract [en]

    Graphene is, due to its extraordinary properties, a promising material for future electronic applications. A common process for the production of large area epitaxial graphene is a high temperature annealing process of atomically flat surfaces from hexagonal silicon carbide. This procedure is very promising but has the drawback of the formation of a buffer layer consisting of a graphene-like sheet, which is covalently bound to the substrate. This buffer layer degenerates the properties of the graphene above and needs to be avoided. We are presenting the combination of a high temperature process for the graphene production with a newly developed substrate of (0 0 1)-oriented cubic silicon carbide. This combination is a promising candidate to be able to supply large area homogenous epitaxial graphene on silicon carbide without a buffer layer. We are presenting the new substrate and first samples of epitaxial graphene on them. Results are shown using low energy electron microscopy and diffraction, photoelectron angular distribution and X-ray photoemission spectroscopy. All these measurements indicate the successful growth of a buffer free few layer graphene on a cubic silicon carbide surface. On our large area samples also the epitaxial relationship between the cubic substrate and the hexagonal graphene could be clarified.

  • 34.
    Hupfer, Thomas
    et al.
    University of Erlangen-Nuremberg, Germany.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Jokubavicius, Valdas
    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.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Modeling of the Mass Transport during Homo-Epitaxial Growth of Silicon Carbide by Fast Sublimation Epitaxy2013Conference paper (Refereed)
    Abstract [en]

    Ballistic and diffusive growth regimes in the Fast Sublimation Growth Process of silicon carbide can be determined using suggested theoretical model for the mean free path calculations. The influences of temperature and inert gas pressure on the mass transport for the growth of epitaxial layers were analyzed theoretically and experimentally.

  • 35. Jacobson, H.
    et al.
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Ellison, A.
    Tuomi, T.
    Optoelectronics Laboratory, Helsinki University of Technology, P.O. Box 3000, 02015 TKK, Finland.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Dislocation-evolution in 4H-SiC epitaxial layers2002In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 91, no 10 I, p. 6354-Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 36. Jacobson, H
    et al.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Raback, P
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Helsinki Univ Technol, Optoelect Lab, FI-02015 Helsinki, Finland.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Lateral enlargement of silicon carbide crystals2002In: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, p. 39-42Conference paper (Refereed)
    Abstract [en]

    A new growth technique for lateral enlargement of silicon carbide crystals is presented. The technique is based on sublimation growth but modified with respect to temperature gradients and geometry as compared to conventional setup. Simulation of the temperature distribution for lateral growth as well as the growth mechanism is discussed. Synchrotron white beam x-ray topographs have been evaluated concerning threading defects along the 0001 direction. Finally, a comparison between laterally grown 4H, 6H-silicon carbide and a commercial 4H-silicon carbide wafer is demonstrated, and shows that this growth technique makes it possible to enlarge seed crystals without screw dislocations and micropipes along the 0001 direction.

  • 37. Jacobson, H.
    et al.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Raback, P.
    Råback, P., Center of Scientific Computing, Box 405, FIN-02101 Espoo, Finland.
    Syväjärvi, Mikael
    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 .
    Tuomi, T.
    Optoelectronics Laboratory, Helsinki University of Technology, P.O. Box 3000, 02015 TKK, Finland.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lateral enlargement of silicon carbide crystals2004In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 270, no 1-2Article in journal (Refereed)
    Abstract [en]

    A new growth technique for lateral enlargement of silicon carbide crystals is presented and evaluated. The technique is based on PVT growth but modified with respect to temperature gradients and geometry as compared to conventional setup. Simulation of the temperature distribution for lateral growth as well as the growth mechanism is discussed. High-resolution X-ray diffraction and synchrotron white beam X-ray topography have been evaluated concerning structural defects. The results show that this growth technique makes it possible to enlarge seed crystals without threading screw dislocations and micropipes along the 0001 direction, but stacking faults are introduced due to the crystal stacking sequence along the <11¯00> directions. © 2004 Elsevier B.V.

  • 38. Jacobson, H.
    et al.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Kakanakova-Georgieva, Anelia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Tuomi, T.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Structural impact of LPE buffer layer on sublimation grown 4H-SiC epilayers2003In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 256, no 3-4, p. 276-282Article in journal (Refereed)
    Abstract [en]

    The objective of this work was to study the effect of a liquid phase epitaxy buffer layer on the development of defects in sublimation grown epitaxial layers of 4H-SiC. The results were analyzed with the aid of optical microscope, scanning electron microscope, high-resolution X-ray diffraction and synchrotron white beam X-ray topography. A pronounced effect of the liquid phase epitaxy buffer layer on formation of dislocations and micropipes is observed in the sublimation epitaxy layers. It has been shown that during sublimation growth of epilayer with a thin liquid phase epitaxy buffer layer (0.1µm) defects may undergo transformation and stacking faults can be formed. Sublimation grown epilayers grown on a thick liquid phase epitaxy buffer layer (1µm) also showed a symmetrical distribution of misfit dislocations along the <112¯0> and [11¯00] directions. © 2003 Elsevier B.V. All rights reserved.

  • 39.
    Jacobsson, Henrik
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Tuomi, T
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Helsinki Univ Technol, Optoelect Lab, FI-02015 Helsinki, Finland.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    High-resolution XRD evaluation of thick 4H-SiC epitaxial layers2001In: Materials Science Forum, Vols. 353-356, 2001, Vol. 353-3, p. 291-294Conference paper (Refereed)
    Abstract [en]

    4H-SiC commercial wafers and sublimation grown epitaxial layers with a thickness of 100 mum have been studied concerning crystalline structure. The substrate wafers and the epitaxial layers have been separately investigated by high-resolution x-ray diffraction (HRXRD) and synchrotron white beam x-ray topography (SWBXT). The results show that the structural quality was improved in the epitaxial layers in the < 11 (2) over bar0 > and <(1) over bar 100 > directions, concerning domain distribution, lattice plane misorientation, mosaicity, and strain? compared with the substrates. Misoriented domains have merged together to form larger domains while the tilt between the domains was reduced, which resulted in non-splitting in diffraction curves. It is also clear that if the misorientation in the substrate gets too large, we can only see a slight decrease in the misorientation in the layer. At some positions on the substrates there were block structure (mosaicity). omega -rocking curves from epilayers at the same position showed smaller full width at half-maximum (FWHM) values and more uniform and narrow peaks. Curvature was almost the same in grown epilayers compared with the substrates. The shape of the grown epitaxial layers nas concave similarly to the substrates.

  • 40.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hens, P.
    University of Erlangen-Nuremberg.
    Liljedahl, Richard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, M.
    University of Erlangen-Nuremberg.
    Wellmann, P.
    University of Erlangen-Nuremberg.
    Sano, S.
    ADMAP INC. 16-2, Tamahara 3-chome, Tamano, Okayama.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kamiyama, S.
    Meijo University, Nagoya .
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Effects of source material on epitaxial growth of fluorescent SiC2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 522, p. 7-10Article in journal (Refereed)
    Abstract [en]

    The growth of fluorescent SiC using Fast Sublimation Growth Process was demonstrated using different types of SiC source materials. These were prepared by (i) high-temperature hot pressing, (ii) chemical vapor deposition and (iii) physical vapor transport. The optimized growth rates of 50 μm/h, 170 μm/h and 200 μm/h were achieved using the three types of sources, respectively. The best results in respect to growth rates are obtained using higher density sources. Fluorescent SiC layers with mirror-like morphology, very good crystal quality and yellowish or warm white light photoluminescence at room temperature were grown using all three types of the source materials.

  • 41.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Huang, Ho Hsuan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Schimmel, Saskia
    University of Erlangen-Nuremberg, Germany.
    Liljedahl, Rickard
    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.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Towards Bulk-Like 3C-SiC Growth Using Low Off-Axis Substrates2013Conference paper (Other academic)
  • 42.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Huang, Ho-Hsuan
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Schimmel, Saskia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    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.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Towards bulk-like 3C-SiC growth using low off-axis substrates2013In: SILICON CARBIDE AND RELATED MATERIALS 2012, Trans Tech Publications , 2013, Vol. 740-742, p. 275-278Conference paper (Refereed)
    Abstract [en]

    Bulk-like 3C-SiC was grown on 1.2 degrees low off-axis 6H-SiC substrates using a sublimation epitaxy technique. The effects of temperature ramp-up and increase in layer thickness on the 3C-SiC domain formation were explored. The temperature ramp-up had no significant effect on the domain size. The domain size was considerably increased and the crystal quality was significantly improved by increasing the thickness of the layer towards bulk-like material. Average full width at half maximum values of 149 arcsec and 65 arcsec were measured in samples with thicknesses of 305 mu m and 1080 mu m, respectively, at a footprint of 1x3 mm(2). This result implies that heteropeitaxial growth of 3C-SiC on low off-axis 6H-SiC substrates by a sublimation method can be used to prepare 3C-SiC seeds or can be further developed for growth of bulk 3C-SiC material.

  • 43.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Liljedahl, Rickard
    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.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Morphological and Optical Stability in Growth of Fluorescent SiC on Low Off-Axis Substrates2013In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 740-742, p. 19-22Article in journal (Refereed)
    Abstract [en]

    Fluorescent silicon carbide was grown using the fast sublimation growth process on low off-axis 6H-SiC substrates. In this case, the morphology of the epilayer and the incorporation of dopants are influenced by the Si/C ratio. Differently converted tantalum foils were introduced into the growth cell in order to change vapor phase stochiometry during the growth. Fluorescent SiC grown using fresh and fully converted tantalum foils contained morphological instabilities leading to lower room temperature photoluminescence intensity while an improved morphology and optical stability was achieved with partly converted tantalum foil. This work reflects the importance of considering the use of Ta foil in sublimation epitaxy regarding the morphological and optical stability in fluorescent silicon carbide.

  • 44.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Liljedahl, Rickard
    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.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Morphological and optical stability in growth of fluorescent SiCon low off-axis substrates2013Conference paper (Other academic)
  • 45.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Richard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Yiyu
    Technical University of Denmark, Lyngby.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Kamiyama, Satoshi
    Meijo University, Nagoya.
    Yakimova, Rositza
    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.
    Geometrical Control of 3C and 6H-SiC Nucleation on Low Off-Axis Substrates2011In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 679-680, p. 103-106Article in journal (Refereed)
    Abstract [en]

    Growth of 3C or 6H-SiC epilayers on low off-axis 6H-SiC substrates can be mastered by changing the size of the on axis plane formed by long terraces in the epilayer using geometrical control. The desired polytype can be selected in thick (~200 µm) layers of both 6H-SiC and 3C-SiC polytypes on substrates with off-orientation as low as 1.4 and 2 degrees. The resultant crystal quality of the 3C and the 6H-SiC epilayers, grown under the same process parameters, deteriorates when lowering the off-orientation of the substrate.

  • 46.
    Jokubavicius, Valdas
    et al.
    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.
    Yakimova, Rositsa
    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.
    Stability in growth of 6H-SiC and 3C-SiC for LEDs and solar cells2012In: 2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE , 2012Conference paper (Refereed)
    Abstract [en]

    6H- and 3C-SiC layers were grown using a sublimation based process. The polytype balance is mainly given by the substrate orientation and growth temperature. This paves the way to use 6H- and 3C-SiC in optoelectronic applications.

  • 47.
    Jokubavicius, Valdas
    et al.
    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.
    Hens, Philip
    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.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    On stabilization of 3C-SiC using low off-axis 6H-SiC substrates2012Conference paper (Refereed)
    Abstract [en]

    Heteroepitaxial growth of 3C-SiC on 0.8 and 1.2 degree off-oriented 6H-SiC substrates was studied using a sublimation growth process. The 3C-SiC layers were grown at high growth rates with layer thickness up to 300 µm. The formation and the quality of 3C-SiC are influenced by the off-orientation of the substrate, the growth temperature (studied temperature range from 1750 oC to 1850oC), and the growth ambient (vacuum at 5*10-5 mbar and nitrogen at 5*10-1 mbar). The largest domains of 3C-SiC and the lowest number of double positioning boundaries were grown using nitrogen ambient and the highest growth temperature. The combined use of low off-axis substrate and high growth rate is a potential method to obtain material with bulk properties.

  • 48.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Vasiliauskas, Remigijus
    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.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Macrodefects in cubic silicon carbide crystals2010In: Materials Science Forum, Vols. 645-648, Transtec Publications; 1999 , 2010, Vol. 645-648, p. 375-378Conference paper (Refereed)
    Abstract [en]

    Different sublimation growth conditions of 3C-SiC approaching a bulk process have been investigated with the focus on appearance of macrodefects. The growth rate of 3C-SiC crystals grown on 6H-SiC varied from 380 to 460 mu m/h with the thickness of the crystals from 190 to 230 mu m, respectively. The formation of macrodefects with void character was revealed at the early stage of 3C-SiC crystal growth. The highest concentration of macrodefects appears in the vicinity of the domain in samples grown under high temperature gradient: and fastest temperature ramp up. The formation of macrodefects was related to carbon deficiency which appear due to high Si/C ratio which is used to enable formation of the 3C-SiC polytype.

  • 49.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xinyu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yazdi, Gholamreza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Growth optimization and applicability of thick on-axis SiC layers using sublimation epitaxy in vacuum2016In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 448, p. 51-57Article in journal (Refereed)
    Abstract [en]

    We demonstrate growth of thick SiC layers (100–200 µm) on nominally on-axis hexagonal substrates using sublimation epitaxy in vacuum (10−5 mbar) at temperatures varying from 1700 to 1975 °C with growth rates up to 270 µm/h and 70 µm/h for 6H- and 4H–SiC, respectively. The stability of hexagonal polytypes are related to process growth parameters and temperature profile which can be engineered using different thermal insulation materials and adjustment of the induction coil position with respect to the graphite crucible. We show that there exists a range of growth rates for which single-hexagonal polytype free of foreign polytype inclusions can be maintained. Further on, foreign polytypes like 3C–SiC can be stabilized by moving out of the process window. The applicability of on-axis growth is demonstrated by growing a 200 µm thick homoepitaxial 6H–SiC layer co-doped with nitrogen and boron in a range of 1018 cm−3 at a growth rate of about 270 µm/h. Such layers are of interest as a near UV to visible light converters in a monolithic white light emitting diode concept, where subsequent nitride-stack growth benefits from the on-axis orientation of the SiC layer.

  • 50.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Silicon Carbide Surface Cleaning and Etching2018In: Advancing Silicon Carbide Electronics Technology I / [ed] Konstantinos Zekentes and Konstantin Vasilevskiy, Materials Research Forum LLC , 2018, p. 1-26Chapter in book (Refereed)
    Abstract [en]

    Silicon carbide (SiC) surface cleaning and etching (wet, electrochemical, thermal) are important technological processes in preparation of SiC wafers for crystal growth, defect analysis or device processing. While removal of organic, particulate and metallic contaminants by chemical cleaning is a routine process in research and industrial production, the etching which, in addition to structural defects analysis, can also be used to modify wafer surface structure, is very interesting for development of innovative device concepts. In this book chapter we review SiC chemical cleaning and etching procedures and present perspectives of SiC etching for new device development.

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