Research Progress on the Growth of SiC Single Crystal via High Temperature Solution Growth Method

Abstract

Abstract: As a third-generation semiconductor material, silicon carbide (SiC) has excellent properties such as wide bandgap, high thermal conductivity, high saturation electron drift velocity, strong radiation resistance, good thermal and chemical stability, et al. It has great application potential in high temperature, high power, high frequency power electronic devices and radio frequency devices. The production of high-quality, large-size, and low-cost SiC single crystal substrates is a prerequisite for large-scale applications of SiC devices. However, the supply of SiC single crystal substrates still faces some challenges, such as high defect density, low yield and high cost. High temperature solution growth (HTSG) technique, with top seeded solution growth (TSSG) as the main technical model at present, has advantages of fabrication of SiC with low defects density, easy to enlarge diameter, and easy to obtain p-type doping. In the future, it is expected to become one of the mainstream technologies to mass produce SiC single crystals. In this paper, the development of SiC single crystal grown by TSSG is reviewed firstly. Then the principle and growth process of SiC single crystal growth by TSSG are introduced and analyzed. The research progress of TSSG for SiC single crystal growth is summarized from crystal growth thermodynamics and kinetics. The unique advantages of this technology are summarized. Finally, the future research direction and challenges of this method are given.

Key words: wide bandgap semiconductor, SiC, high temperature solution growth (HTSG), top seeded solution growth (TSSG), flux, crystal growth

CLC Number:

O734

WANG Guobin, LI Hui, SHENG Da, WANG Wenjun, CHEN Xiaolong. Research Progress on the Growth of SiC Single Crystal via High Temperature Solution Growth Method[J]. Journal of Synthetic Crystals, 2022, 51(1): 3-20.

References

[1] KIMOTO T. Material science and device physics in SiC technology for high-voltage power devices[J]. Japanese Journal of Applied Physics, 2015, 54(4): 040103.
[2] HAMADA K, NAGAO M, AJIOKA M, et al. SiC: emerging power device technology for next-generation electrically powered environmentally friendly vehicles[J]. IEEE Transactions on Electron Devices, 2015, 62(2): 278-285.
[3] OKUMURA H. Present status and future prospect of widegap semiconductor high-power devices[J]. Japanese Journal of Applied Physics, 2006, 45(10A): 7565-7586.
[4] POWELL A R, SUMAKERIS J J, KHLEBNIKOV Y, et al. Bulk growth of large area SiC crystals[J]. Materials Science Forum, 2016, 858: 5-10.
[5] NARUMI T, CHAUSSENDE D, YOSHIKAWA T. 3C-, 4H-, and 6H-SiC crystal habitus and interfacial behaviours in high temperature Si-based solvents[J]. CrystEngComm, 2020, 22(20): 3489-3496.
[6] KAWANISHI S, NAGAMATSU Y, YOSHIKAWA T, et al. Availability of Cr-rich Cr-Si solvent for rapid solution growth of 4H-SiC[J]. Journal of Crystal Growth, 2020, 549: 125877.
[7] HYUN K, KIM S J, TAISHI T. Effect of cobalt addition to Si-Cr solvent in top-seeded solution growth[J]. Applied Surface Science, 2020, 513: 145798.
[8] TOKUDA Y, UEHIGASHI H, MURATA K, et al. Fabrication of 4H-SiC PiN diodes on substrate grown by HTCVD method[J]. Japanese Journal of Applied Physics, 2020, 59(SG): SGGD07.
[9] TOKUDA Y, MAKINO E, SUGIYAMA N, et al. Stable and high-speed SiC bulk growth without dendrites by the HTCVD method[J]. Journal of Crystal Growth, 2016, 448: 29-35.
[10] TOKUDA Y, HOSHINO N, KUNO H, et al. Fast 4H-SiC bulk growth by high-temperature gas source method[J]. Materials Science Forum, 2020, 1004: 5-13.
[11] OKAMOTO T, KANDA T, TOKUDA Y, et al. Development of 150-mm 4H-SiC substrates using a high-temperature chemical vapor deposition method[J]. Materials Science Forum, 2020, 1004: 14-19.
[12] HOFMANN D H, MÜLLER M H. Prospects of the use of liquid phase techniques for the growth of bulk silicon carbide crystals[J]. Materials Science and Engineering: B, 1999, 61/62: 29-39.
[13] 刘春俊.SiC单晶生长技术研究现状[J].中国照明电器,2017(10):18-21.
LIU C J. Research status of SiC single crystal growth[J]. China Light & Lighting, 2017(10): 18-21(in Chinese).
[14] DAIKOKU H, KADO M, SEKI A, et al. Solution growth on concave surface of 4H-SiC crystal[J]. Crystal Growth & Design, 2016, 16(3): 1256-1260.
[15] EPELBAUM B M, HOFMANN D, MÜLLER M, et al. Top-seeded solution growth of bulk SiC: search for fast growth regimes[J]. Materials Science Forum, 2000, 338/339/340/341/342: 107-110.
[16] KUSUNOKI K, MUNETOH S, KAMEI K, et al. Solution growth of self-standing 6H-SiC single crystal using metal solvent[J]. Materials Science Forum, 2004, 457/458/459/460: 123-126.
[17] KUSUNOKI K, KAMEI K, UEDA Y, et al. Crystalline quality evaluation of 6H-SiC bulk crystals grown from Si-Ti-C ternary solution[J]. Materials Science Forum, 2005, 483/484/485: 13-16.
[18] KUSUNOKI K, KAMEI K, OKADA N, et al. Solution growth of SiC crystal with high growth rate using accelerated crucible rotation technique[J]. Materials Science Forum, 2006, 527/528/529: 119-122.
[19] KAMEI K, KUSUNOKI K, YASHIRO N, et al. Solution growth of single crystalline 6H, 4H-SiC using Si-Ti-C melt[J]. Journal of Crystal Growth, 2009, 311(3): 855-858.
[20] YASHIRO N, KUSUNOKI K, KAMEI K, et al. Solution growth and crystallinity characterization of bulk 6H-SiC[J]. Materials Science Forum, 2010, 645/646/647/648: 33-36.
[21] KUSUNOKI K, YASHIRO N, OKADA N, et al. Growth of large diameter 4H-SiC by TSSG technique[J]. Materials Science Forum, 2013, 740/741/742: 65-68.
[22] KUSUNOKI K, KAMEI K, OKADA N, et al. Top-seeded solution growth of 3 inch diameter 4H-SiC bulk crystal using metal solvents[J]. Materials Science Forum, 2014, 778/779/780: 79-82.
[23] DANNO K, SAITOH H, SEKI A, et al. High-speed growth of high-quality 4H-SiC bulk by solution growth using Si-Cr based melt[J]. Materials Science Forum, 2010, 645/646/647/648: 13-16.
[24] KUSUNOKI K, KISHIDA Y, SEKI K. Solution growth of 4-inch diameter SiC single crystal using Si-Cr based solvent[J]. Materials Science Forum, 2019, 963: 85-88.
[25] DAIKOKU H, KADO M, SAKAMOTO H, et al. Top-seeded solution growth of 4H-SiC bulk crystal using Si-Cr based melt[J]. Materials Science Forum, 2012, 717/718/719/720: 61-64.
[26] KADO M, DAIKOKU H, SAKAMOTO H, et al. High-speed growth of 4H-SiC single crystal using Si-Cr based melt[J]. Materials Science Forum, 2013, 740/741/742: 73-76.
[27] KUSUNOKI K, SEKI K, KISHIDA Y, et al. Development of solvent inclusion free 4H-SiC off-axis wafer grown by the top-seeded solution growth technique[J]. Materials Science Forum, 2018, 924: 31-34.
[28] ZHANG Z S, CHEN L, DENG J, et al. Intrinsic ferromagnetism in 4H-SiC single crystal induced by Al-doping[J]. Applied Physics A, 2020, 126(9): 1-8.
[29] YAKIMOVA R, TUOMINEN M, BAKIN A S, et al. Silicon carbide liquid phase epitaxy in the Si-Sc-C system[M]//NAKASHIMA S, MATSUNAMI H, YOSHIDA S, et al. Silicon Carbide and Related Materials 1995. Bristol; Iop Publishing Ltd. 1996: 101-104.
[30] NELSON W E, HALDEN F A, ROSENGREEN A. Growth and properties of β-SiC single crystals[J]. Journal of Applied Physics, 1966, 37(1): 333-336.
[31] CHAUSSENDE D, OHTANI N. Silicon carbide[M]//Single Crystals of Electronic Materials. Amsterdam: Elsevier, 2019: 129-179.
[32] KAWAMURA F, OGURA T, IMADE M, et al. Growth of 2H-SiC single crystals in a Li-based flux[J]. Materials Letters, 2008, 62(6/7): 1048-1051.
[33] IMADE M, OGURA T, UEMURA M, et al. Growth of 2H-SiC single crystals in a C-Li-Si ternary melt system[J]. Materials Science Forum, 2008, 600/601/602/603: 55-58.
[34] SUZUKI K, KUSUNOKI K, YASHIRO N, et al. Solution growth of single crystalline 6H-SiC from Si-Ti-C ternary solution[J]. Key Engineering Materials, 2007, 352: 89-94.
[35] HATTORI R, KUSUNOKI K, YASHIRO N, et al. Solution growth of off-axis 4H-SiC for power device application[J]. Materials Science Forum, 2008, 600/601/602/603: 179-182.
[36] TANAKA R, SEKI K, KOMIYAMA S, et al. Solution growth of SiC crystals In Si-Ti and Si-Ge-Ti solvents[J]. Materials Science Forum, 2008, 600/601/602/603: 59-62.
[37] KAMEI K, KUSUNOKI K, YASHIRO N, et al. Crystallinity evaluation of 4H-SiC single crystal grown by solution growth technique using Si-Ti-C solution[J]. Materials Science Forum, 2012, 717/718/719/720: 45-48.
[38] KUSUNOKI K, OKADA N, KAMEI K, et al. Top-seeded solution growth of three-inch-diameter 4H-SiC using convection control technique[J]. Journal of Crystal Growth, 2014, 395: 68-73.
[39] KUSUNOKI K, KAMEI K, SEKI K, et al. Nitrogen doping of 4H-SiC by the top-seeded solution growth technique using Si-Ti solvent[J]. Journal of Crystal Growth, 2014, 392: 60-65.
[40] SHIRAI T, DANNO K, SEKI A, et al. Solution growth of p-type 4H-SiC bulk crystals with low resistivity[J]. Materials Science Forum, 2014, 778/779/780: 75-78.
[41] MITANI T, KOMATSU N, TAKAHASHI T, et al. 4H-SiC growth from Si-Cr-C solution under Al and N co-doping conditions[J]. Materials Science Forum, 2015, 821/822/823: 9-13.
[42] DANNO K, YAMAGUCHI S, KIMOTO H, et al. Trials of solution growth of dislocation-free 4H-SiC bulk crystals[J]. Materials Science Forum, 2016, 858: 19-22.
[43] HYUN K Y, TAISHI T, SUZUKI K, et al. Experimental determination of carbon solubility in Si_0.56Cr_0.4M_0.04 (M=transition metal) solvents for solution growth of SiC[J]. Materials Science Forum, 2018, 924: 43-46.
[44] KOMATSU N, MITANI T, HAYASHI Y, et al. Influence of additives on surface smoothness and polytype stability in solution growth of n-type 4H-SiC[J]. Materials Science Forum, 2018, 924: 55-59.
[45] TAISHI T, TAKAHASHI M, TSUCHIMOTO N, et al. Solution growth of SiC from the crucible bottom with dipping under unsaturation state of carbon in solvent[J]. Materials Science Forum, 2018, 924: 51-54.
[46] HYUN K, KIM S J, TAISHI T. Estimation of C solubility at SiC saturation from the reaction of carbon crucible with Si-Cr solvent for top-seeded solution growth[J]. Acta Physica Polonica A, 2019, 135(5): 1012-1017.
[47] KAWANISHI S, YOSHIKAWA T, SHIBATA H. Thermomigration of molten Cr-Si-C alloy in 4H-SiC at 1 873~2 273 K[J]. Journal of Crystal Growth, 2019, 518: 73-80.
[48] YOSHIKAWA T, KAWANISHI S, TANAKA T. Solution growth of silicon carbide using Fe-Si solvent[J]. Japanese Journal of Applied Physics, 2010, 49(5): 051302.
[49] KAWANISHI S, YOSHIKAWA T, MORITA K, et al. Solution growth behavior of SiC by a temperature difference method using Fe-Si solvent[J]. Journal of Crystal Growth, 2013, 381: 121-126.
[50] KAWANISHI S, YOSHIKAWA T. In situ interface observation of 3C-SiC nucleation on basal planes of 4H-SiC during solution growth of SiC from molten Fe-Si alloy[J]. JOM, 2018, 70(7): 1239-1247.
[51] SEKI K, ALEXANDER, KOZAWA S, et al. Formation process of 3C-SiC on 6H-SiC (0001) by low-temperature solution growth in Si-Sc-C system[J]. Journal of Crystal Growth, 2011, 335(1): 94-99.
[52] MARUYAMA S, ONUMA A, KURASHIGE K, et al. High-throughput screening of Si-Ni flux for SiC solution growth using a high-temperature laser microscope observation and secondary ion mass spectroscopy depth profiling[J]. ACS Combinatorial Science, 2013, 15(6): 287-290.
[53] GAO M X, PAN Y, OLIVEIRA F J, et al. The growth of SiC crystals from CoSi molten alloy fluxes[J]. Materials Science Forum, 2006, 514/515/516: 343-347.
[54] HARADA S, HATASA G, MURAYAMA K, et al. Solvent design for high-purity SiC solution growth[J]. Materials Science Forum, 2017, 897: 32-35.
[55] HORIO A, HARADA S, KOIKE D, et al. Polytype control by activity ratio of silicon to carbon during SiC solution growth using multicomponent solvents[J]. Japanese Journal of Applied Physics, 2016, 55(1S): 01AC01.
[56] KOMATSU N, MITANI T, TAKAHASHI T, et al. Change in surface morphology by addition of impurity elements in 4H-SiC solution growth with Si solvent[J]. Materials Science Forum, 2015, 821/822/823: 14-17.
[57] MITANI T, KOMATSU N, TAKAHASHI T, et al. Effect of aluminum addition on the surface step morphology of 4H-SiC grown from Si-Cr-C solution[J]. Journal of Crystal Growth, 2015, 423: 45-49.
[58] KOMATSU N, MITANI T, HAYASHI Y, et al. Modification of the surface morphology of 4H-SiC by addition of Sn and Al in solution growth with SiCr solvents[J]. Journal of Crystal Growth, 2017, 458: 37-43.
[59] DAIKOKU H, KAWANISHI S, ISHIKAWA T, et al. Density, surface tension, and viscosity of liquid Si-Cr alloys and influence on temperature and fluid flow during solution growth of SiC[J]. The Journal of Chemical Thermodynamics, 2021, 160: 106476.
[60] ZHU C, HARADA S, SEKI K, et al. Influence of solution flow on step bunching in solution growth of SiC crystals[J]. Crystal Growth & Design, 2013, 13(8): 3691-3696.
[61] KURASHIGE K, AOSHIMA M, TAKEI K, et al. Effect of forced convection by crucible design in solution growth of SiC single crystal[J]. Materials Science Forum, 2015, 821/822/823: 22-25.
[62] ARIYAWONG K, SHIN Y J, DEDULLE J M, et al. Analysis of macrostep formation during top seeded solution growth of 4H-SiC[J]. Crystal Growth & Design, 2016, 16(6): 3231-3236.
[63] HAYASHI Y, MITANI T, KOMATSU N, et al. Control of temperature distribution to suppress macro-defects in solution growth of 4H-SiC crystals[J]. Journal of Crystal Growth, 2019, 523: 125151.
[64] LIU B T, YU Y, TANG X, et al. Optimization of crucible and heating model for large-sized silicon carbide ingot growth in top-seeded solution growth[J]. Journal of Crystal Growth, 2020, 533: 125406.
[65] KIM Y G, CHOI S H, SHIN Y J, et al. Modification of crucible shape in top seeded solution growth of SiC crystal[J]. Materials Science Forum, 2018, 924: 47-50.
[66] HA M T, YU Y J, SHIN Y J, et al. Flow modification enhancing the growth rate in top seeded solution growth of SiC crystals[J]. RSC Advances, 2019, 9(45): 26327-26337.
[67] MERCIER F, DEDULLE J M, CHAUSSENDE D, et al. Coupled heat transfer and fluid dynamics modeling of high-temperature SiC solution growth[J]. Journal of Crystal Growth, 2010, 312(2): 155-163.
[68] MERCIER F, NISHIZAWA S I. Comparative numerical study of the effects of rotating and traveling magnetic fields on the carbon transport in the solution growth of SiC crystals[J]. Journal of Crystal Growth, 2013, 362: 99-102.
[69] TAKEHARA Y, SEKIMOTO A, OKANO Y, et al. Explainable machine learning for the analysis of transport phenomena in top-seeded solution growth of SiC single crystal[J]. Journal of Thermal Science and Technology, 2021, 16(1): JTST0009.
[70] TAKEHARA Y, SEKIMOTO A, OKANO Y, et al. Bayesian optimization for a high- and uniform-crystal growth rate in the top-seeded solution growth process of silicon carbide under applied magnetic field and seed rotation[J]. Journal of Crystal Growth, 2020, 532: 125437.
[71] WANG L, HORIUCHI T, SEKIMOTO A, et al. Three-dimensional numerical analysis of Marangoni convection occurring during the growth process of SiC by the RF-TSSG method[J]. Journal of Crystal Growth, 2019, 520: 72-81.
[72] LIU B T, YU Y, TANG X, et al. Improvement of growth interface stability for 4-inch silicon carbide crystal growth in TSSG[J]. Crystals, 2019, 9(12): 653.
[73] LIU B T, YU Y, TANG X, et al. Influence of silicon melt convection on interface instability in large-size silicon carbide solution growth[J]. Journal of Crystal Growth, 2019, 527: 125248.
[74] HORIUCHI T, WANG L, SEKIMOTO A, et al. The effect of crucible rotation and crucible size in top-seeded solution growth of single-crystal silicon carbide[J]. Crystal Research and Technology, 2019, 54(5): 1900014.
[75] HORIUCHI T, WANG L, SEKIMOTO A, et al. Adjoint-based sensitivity analysis for the optimal crucible temperature profile in the RF-Heating TSSG-SiC crystal growth process[J]. Journal of Crystal Growth, 2019, 517: 59-63.
[76] HA M T, SHIN Y J, BAE S Y, et al. Effect of hot-zone aperture on the growth behavior of SiC single crystal produced via top-seeded solution growth method[J]. Journal of the Korean Ceramic Society, 2019, 56(6): 589-595.
[77] WANG L, HORIUCHI T, SEKIMOTO A, et al. Numerical investigation of the effect of static magnetic field on the TSSG growth of SiC[J]. Journal of Crystal Growth, 2018, 498: 140-147.
[78] LEFEBURE J, DEDULLE J M, OUISSE T, et al. Modeling of the growth rate during top seeded solution growth of SiC using pure silicon as a solvent[J]. Crystal Growth & Design, 2012, 12(2): 909-913.
[79] MUKAIYAMA Y, IIZUKA M, VOROB'EV A, et al. Numerical investigation of the effect of shape change in graphite crucible during top-seeded solution growth of SiC[J]. Journal of Crystal Growth, 2017, 475: 178-185.
[80] YAMAMOTO T, ADKAR N, OKANO Y, et al. Numerical investigation of the transport phenomena occurring in the growth of SiC by the induction heating TSSG method[J]. Journal of Crystal Growth, 2017, 474: 50-54.
[81] YAMAMOTO T, OKANO Y, UJIHARA T, et al. Global simulation of the induction heating TSSG process of SiC for the effects of Marangoni convection, free surface deformation and seed rotation[J]. Journal of Crystal Growth, 2017, 470: 75-88.
[82] HA M T, SHIN Y J, LEE M H, et al. Effects of the temperature gradient near the crystal-melt interface in top seeded solution growth of SiC crystal[J]. Physica Status Solidi (a), 2018, 215(20): 1701017.
[83] TSUNOOKA Y, KOKUBO N, HATASA G, et al. High-speed prediction of computational fluid dynamics simulation in crystal growth[J]. CrystEngComm, 2018, 20(41): 6546-6550.
[84] KAWANISHI S, KAMIKO M, YOSHIKAWA T, et al. Analysis of the spiral step structure and the initial solution growth behavior of SiC by real-time observation of the growth interface[J]. Crystal Growth & Design, 2016, 16(9): 4822-4830.
[85] ONUMA A, MARUYAMA S, KOMATSU N, et al. Quantitative analysis of nanoscale step dynamics in high-temperature solution-grown single crystal 4H-SiC via in situ confocal laser scanning microscope[J]. Crystal Growth & Design, 2017, 17(5): 2844-2851.
[86] YAKIMOVA R, TUOMINEN M, BAKIN A S, et al. Silicon carbide liquid phase epitaxy in the Si-Sc-C system[C]∥proceedings of the International Conference on Silicon Carbide and Related Materials 1995 (ICSCRM-95). Iop Publishing Ltd: BRISTOL, 1996.
[87] KHAN M N, NISHIZAWA S I, ARAI K. Healing defects in SiC wafers by liquid-phase epitaxy in Si melts[J]. Journal of Crystal Growth, 2003, 254(1/2): 137-143.
[88] UJIHARA T, MUNETOH S, KUSUNOKI K, et al. Crystal quality evaluation of 6H-SiC layers grown by liquid phase epitaxy around micropipes using micro-Raman scattering spectroscopy[J]. Materials Science Forum, 2004, 457/458/459/460: 633-636.
[89] UJIHARA T, MUNETOH S, KUSUNOKI K, et al. Crystal quality of a 6H-SiC layer grown over macrodefects by liquid-phase epitaxy: a Raman spectroscopic study[J]. Thin Solid Films, 2005, 476(1): 206-209.
[90] KUSUNOKI K, KAMEI K, YASHIRO N, et al. Liquid phase epitaxy of 4H-SiC layers on on-axis PVT grown substrates[J]. Materials Science Forum, 2009, 615/616/617: 137-140.
[91] UJIHARA T, KOZAWA S, SEKI K, et al. Conversion mechanism of threading screw dislocation during SiC solution growth[J]. Materials Science Forum, 2012, 717/718/719/720: 351-354.
[92] YAMAMOTO Y, HARADA S, SEKI K, et al. High-efficiency conversion of threading screw dislocations in 4H-SiC by solution growth[J]. Applied Physics Express, 2012, 5(11): 115501.
[93] HARADA S, YAMAMOTO Y, SEKI K, et al. Evolution of threading screw dislocation conversion during solution growth of 4H-SiC[J]. APL Materials, 2013, 1(2): 022109.
[94] HARADA S, YAMAMOTO Y, SEKI K, et al. Reduction of threading screw dislocation utilizing defect conversion during solution growth of 4H-SiC[J]. Materials Science Forum, 2013, 740/741/742: 189-192.
[95] YAMAMOTO Y, HARADA S, SEKI K, et al. Effect of surface polarity on the conversion of threading dislocations in solution growth[J]. Materials Science Forum, 2013, 740/741/742: 15-18.
[96] HARADA S, YAMAMOTO Y, SEKI K, et al. Different behavior of threading edge dislocation conversion during the solution growth of 4H-SiC depending on the Burgers vector[J]. Acta Materialia, 2014, 81: 284-290.
[97] YAMAMOTO Y, HARADA S, SEKI K, et al. Low-dislocation-density 4H-SiC crystal growth utilizing dislocation conversion during solution method[J]. Applied Physics Express, 2014, 7(6): 065501.
[98] HARADA S, YAMAMOTO Y, XIAO S, et al. Dislocation conversion during SiC solution growth for high-quality crystals[J]. Materials Science Forum, 2015, 821/822/823: 3-8.
[99] XIAO S Y, HARADA S, MURAYAMA K, et al. Conversion behavior of threading screw dislocations on C face with different surface morphology during 4H-SiC solution growth[J]. Crystal Growth & Design, 2016, 16(11): 6436-6439.
[100] KOMATSU N, MITANI T, HAYASHI Y, et al. Application of defect conversion layer by solution growth for reduction of TSDs in 4H-SiC bulk crystals by PVT growth[J]. Materials Science Forum, 2019, 963: 71-74.
[101] LIU X B, ZHU C, HARADA S, et al. Application of C-face dislocation conversion to 2 inch SiC crystal growth on an off-axis seed crystal[J]. CrystEngComm, 2019, 21(47): 7260-7265.
[102] HAN L B, LIANG L, KANG Y, et al. A review of SiC IGBT: models, fabrications, characteristics, and applications[J]. IEEE Transactions on Power Electronics, 2021, 36(2): 2080-2093.
[103] STRAUBINGER T L, BICKERMANN M, WEINGÄRTNER R, et al. Aluminum p-type doping of silicon carbide crystals using a modified physical vapor transport growth method[J]. Journal of Crystal Growth, 2002, 240(1/2): 117-123.
[104] RASTEGAEV V P, AVROV D D, RESHANOV S A, et al. Features of SiC single-crystals grown in vacuum using the LETI method[J]. Materials Science and Engineering: B, 1999, 61/62: 77-81.