Effect of C/Si Ratio on SiC Fast Homoepitaxial Growth in Vertical Hot-Wall CVD Reactor

doi:10.16553/j.cnki.issn1000-985x.2024.0247

Abstract

Abstract: The homoepitaxial growth mechanism of SiC was studied using both experiment and computational fluid dynamics (CFD) simulation in a vertical hot-wall CVD reactor with high-speed wafer rotation, and the influence of the C/Si ratio on the epitaxial growth rate and carrier doping concentration on the wafer surface were explored. The study reveals that the molar ratio of carbon-containing to silicon-containing species above the wafer surface (referred to as the effective C/Si ratio) deviates from the C/Si ratio at the gas inlet. This discrepancy is believed to be related to the gas species redistribution during the gas transport and diffusion, as well as parasitic deposition of precursors in the gas injector and/or on the hot-wall. The impact of the effective C/Si ratio on the growth rate and doping concentration was investigated. It is demonstrated that the growth rate, doping concentration and their uniformities are primarily influenced by the effective C/Si ratio at the wafer surface rather than the C/Si ratio at the gas inlet. By optimizing the growth conditions, high-quality 6-inch (1 inch=2.54 cm)epitaxial wafer is achieved with thickness and doping uniformity of 1.15% and 2.68%, respectively. 8-inch SiC epitaxial wafer with similar thickness and doping uniformities is obtained. Moreover, SiC epilayer (thickness exceeding 50 μm) with high growth rate is also demonstrated.

Key words: SiC, homoepitaxial, chemical vapor deposition, C/Si ratio, CFD simulation

CLC Number:

CHEN Danying, YAN Long, LUO Jiahao, ZHENG Zhenyu, JIANG Yong, ZHANG Kai, ZHOU Ning, LIAO Chenzi, GUO Shiping. Effect of C/Si Ratio on SiC Fast Homoepitaxial Growth in Vertical Hot-Wall CVD Reactor[J]. Journal of Synthetic Crystals, 2025, 54(4): 569-580.

References

[1] ROCCAFORTE F, FIORENZA P, GRECO G, et al. Emerging trends in wide band gap semiconductors (SiC and GaN) technology for power devices[J]. Microelectronic Engineering, 2018, 187: 66-77.
[2] KIMOTO T, WATANABE H. Defect engineering in SiC technology for high-voltage power devices[J]. Applied Physics Express, 2020, 13(12): 120101.
[3] TSUCHIDA H, KAMATA I, MIYAZAWA T, et al. Recent advances in 4H-SiC epitaxy for high-voltage power devices[J]. Materials Science in Semiconductor Processing, 2018, 78: 2-12.
[4] KURODA N, SHIBAHARA K, YOO W, et al. Step-controlled VPE growth of SiC single crystals at low temperatures[C]//Extended Abstracts of the 1987 Conference on Solid State Devices and Materials. August 25-27, 1987. Nippon Toshi Center, Tokyo, Japan. The Japan Society of Applied Physics, 1987.
[5] UEDA T, NISHINO H, MATSUNAMI H. Crystal growth of SiC by step-controlled epitaxy[J]. Journal of Crystal Growth, 1990, 104(3): 695-700.
[6] KONG H, KIM H J, EDMOND J A, et al. Growth, doping, device development and characterization of CVD beta-SiC epilayers on Si(100) and alpha-SiC(0001)[J]. MRS Online Proceedings Library, 1987, 97(1): 233-245.
[7] KONG H S, GLASS J T, DAVIS R F. Chemical vapor deposition and characterization of 6H-SiC thin films on off-axis 6H-SiC substrates[J]. Journal of Applied Physics, 1988, 64(5): 2672-2679.
[8] KIMOTO T. Bulk and epitaxial growth of silicon carbide[J]. Progress in Crystal Growth and Characterization of Materials, 2016, 62(2): 329-351.
[9] RUPP R, MAKAROV Y N, BEHNER H, et al. Silicon carbide epitaxy in a vertical CVD reactor: experimental results and numerical process simulation[J]. Physica Status Solidi B Basic Research, 1997, 202(1): 281-304.
[10] KIMOTO T, COOPER J A. Fundamentals of Silicon Carbide Technology[M]. Singapore: Wiley, 2014.
[11] MYERS-WARD R L, KORDINA O, SHISHKIN Z, et al. Increased growth rate in a SiC CVD reactor using HCl as a growth additive[J]. Materials Science Forum, 2005, 483/484/485: 73-76.
[12] LA VIA F, GALVAGNO G, FOTI G, et al. 4H SiC epitaxial growth with chlorine addition[J]. Chemical Vapor Deposition, 2006, 12(8/9): 509-515.
[13] LA VIA F, IZZO G, MAUCERI M, et al. 4H-SiC epitaxial layer growth by trichlorosilane (TCS)[J]. Journal of Crystal Growth, 2008, 311(1): 107-113.
[14] PEDERSEN H, LEONE S, HENRY A, et al. Very high growth rate of 4H-SiC epilayers using the chlorinated precursor methyltrichlorosilane (MTS)[J]. Journal of Crystal Growth, 2007, 307(2): 334-340.
[15] YAZDANFAR M, IVANOV I G, PEDERSEN H, et al. Reduction of structural defects in thick 4H-SiC epitaxial layers grown on 4° off-axis substrates[J]. Journal of Applied Physics, 2013, 113(22): 223502.
[16] YAZDANFAR M, DANIELSSON Ö, KORDINA O, et al. Finding the optimum chloride-based chemistry for chemical vapor deposition of SiC[J]. ECS Journal of Solid State Science and Technology, 2014, 3(10): P320-P323.
[17] CHOWDHURY I, CHANDRASEKHAR M V S, KLEIN P B, et al. High growth rate 4H-SiC epitaxial growth using dichlorosilane in a hot-wall CVD reactor[J]. Journal of Crystal Growth, 2011, 316(1): 60-66.
[18] SONG H Z, CHANDRASHEKHAR M V S, SUDARSHAN T S. Study of surface morphology, impurity incorporation and defect generation during homoepitaxial growth of 4H-SiC using dichlorosilane[J]. ECS Journal of Solid State Science and Technology, 2014, 4(3): P71-P76.
[19] KOSHKA Y, LIN H D, MELNYCHUK G, et al. Epitaxial growth of 4H-SiC at low temperatures using CH₃Cl carbon gas precursor: growth rate, surface morphology, and influence of gas phase nucleation[J]. Journal of Crystal Growth, 2006, 294(2): 260-267.
[20] 钮应喜, 杨霏, 温家良, 等. 4英寸碳化硅快速同质外延生长研究[J]. 智能电网, 2014, 2(12): 21-24.
NIU Y X, YANG F, WEN J L, et al. Fast homo-epitaxy growth of 4-inch silicon carbide wafer[J]. Smart Grid, 2014, 2(12): 21-24 (in Chinese).
[21] 闫果果, 张峰, 钮应喜, 等. 氯基条件下4H-SiC衬底的同质外延生长研究[J]. 半导体光电, 2016, 37(3): 353-357.
YAN G G, ZHANG F, NIU Y X, et al. Study on chloride-based homoepitaxial growth on 4° off-axis(0001)4H-SiC substrate[J]. Semiconductor Optoelectronics, 2016, 37(3): 353-357 (in Chinese).
[22] FUJIBAYASHI H, ITO M, ITO H, et al. Development of a 150 mm 4H-SiC epitaxial reactor with high-speed wafer rotation[J]. Applied Physics Express, 2014, 7(1): 015502.
[23] DAIGO Y, ISHIGURO A, ISHII S, et al. High in-wafer uniformity of growth rate and carrier concentration on n-type 4H-SiC epitaxial films achieved by high speed wafer rotation vertical CVD tool[J]. Materials Science Forum, 2018, 924: 88-91.
[24] 韩跃斌, 蒲勇, 施建新, 等. 高速旋转垂直热壁CVD外延生长n型4H-SiC膜的研究[J]. 人工晶体学报, 2023, 52(5): 918-924.
HAN Y B, PU Y, SHI J X, et al. Epitaxial growth study of n-type 4H-SiC films by high-speed wafer rotation vertical hot-wall CVD equipment[J]. Journal of Synthetic Crystals, 2023, 52(5): 918-924 (in Chinese).
[25] DANIELSSON Ö, KARLSSON M, SUKKAEW P, et al. A systematic method for predictive in silico chemical vapor deposition[J]. The Journal of Physical Chemistry C, 2020, 124(14): 7725-7736.
[26] WANG R, MA R H, DUDLEY M. Reduction of chemical reaction mechanism for halide-assisted silicon carbide epitaxial film deposition[J]. Industrial & Engineering Chemistry Research, 2009, 48(8): 3860-3866.
[27] MEZIERE J, UCAR M, BLANQUET E, et al. Modeling and simulation of SiC CVD in the horizontal hot-wall reactor concept[J]. Journal of Crystal Growth, 2004, 267(3/4): 436-451.
[28] CAVALLOTTI C, ROSSI F, RAVASIO S, et al. A kinetic analysis of the growth and doping kinetics of the SiC chemical vapor deposition process[J]. Industrial & Engineering Chemistry Research, 2014, 53(22): 9076-9087.
[29] SONG B T, GAO B, HAN P F, et al. Numerical simulation of gas phase reaction for epitaxial chemical vapor deposition of silicon carbide by methyltrichlorosilane in horizontal hot-wall reactor[J]. Materials, 2021, 14(24): 7532.
[30] SONG B T, GAO B, HAN P F, et al. Surface kinetic mechanisms of epitaxial chemical vapour deposition of 4H silicon carbide growth by methyltrichlorosilane-H₂ gaseous system[J]. Materials, 2022, 15(11): 3768.
[31] ITO M, FUJIBAYASHI H, ITO H, et al. Simulation study of high-speed wafer rotation effects in a vertical reactor for 4H-SiC epitaxial growth on 150 mm substrates[J]. Materials Science Forum, 2014, 778/779/780: 171-174.
[32] MERK H J. The macroscopic equations for simultaneous heat and mass transfer in isotropic, continuous and closed systems[J]. Applied Scientific Research, Section A, 1959, 8(1): 73-99.
[33] VENERONI A, MASI M. Gas-phase and surface kinetics of epitaxial silicon carbide growth involving chlorine-containing species[J]. Chemical Vapor Deposition, 2006, 12(8/9): 562-568.
[34] LU W L, FANG Y L, LI J, et al. Study and reduction of the surface pits in 4H-SiC epitaxial wafer[J]. Journal of Crystal Growth, 2023, 610: 127156.
[35] MITROVIC B, GURARY A, KADINSKI L. On the flow stability in vertical rotating disc MOCVD reactors under a wide range of process parameters[J]. Journal of Crystal Growth, 2006, 287(2): 656-663.
[36] LEONE S, KORDINA O, HENRY A, et al. Gas-phase modeling of chlorine-based chemical vapor deposition of silicon carbide[J]. Crystal Growth & Design, 2012, 12(4): 1977-1984.
[37] CHOKAWA K, DAIGO Y, MIZUSHIMA I, et al. First-principles and thermodynamic analysis for gas phase reactions and structures of the SiC(0001) surface under conventional CVD and Halide CVD environments[J]. Japanese Journal of Applied Physics, 2021, 60(8): 085503.
[38] DANIELSSON Ö, SUKKAEW P, OJAMÄE L, et al. Shortcomings of CVD modeling of SiC today[J]. Theoretical Chemistry Accounts, 2013, 132(11): 1398.
[39] 于海群, 左然, 徐楠, 等. 垂直式MOCVD反应器中热泳力对浓度分布的影响分析[J]. 人工晶体学报, 2012, 41(4): 1059-1065.
YU H Q, ZUO R, XU N, et al. Influence of thermophoretic force on precursor concentration and thin film growth in a vertical MOCVD reactor[J]. Journal of Synthetic Crystals, 2012, 41(4): 1059-1065 (in Chinese).
[40] NISHIZAWA S, PONS M. Growth and doping modeling of SiC-CVD in a horizontal hot-wall reactor[J]. Chemical Vapor Deposition, 2006, 12(8/9): 516-522.
[41] SUDARSHAN T S, RANA T, SONG H Z, et al. Trade-off between parasitic deposition and SiC homoepitaxial growth rate using halogenated Si-precursors[J]. ECS Journal of Solid State Science and Technology, 2013, 2(8): N3079-N3086.
[42] RANA T, CHANDRASHEKHAR M V S, SUDARSHAN T S. Elimination of silicon gas phase nucleation using tetrafluorosilane (SiF₄) precursor for high quality thick silicon carbide (SiC) homoepitaxy[J]. Physica Status Solidi (a), 2012, 209(12): 2455-2462.
[43] MITROVIC B, GURARY A, QUINN W. Process conditions optimization for the maximum deposition rate and uniformity in vertical rotating disc MOCVD reactors based on CFD modeling[J]. Journal of Crystal Growth, 2007, 303(1): 323-329.
[44] DAIGO Y, ISHII S, KOBAYASHI T. Impacts of surface C/Si ratio on in-wafer uniformity and defect density of 4H-SiC homo-epitaxial films grown by high-speed wafer rotation vertical CVD[J]. Japanese Journal of Applied Physics, 2019, 58: SBBK06.
[45] FERRO G, CHAUSSENDE D. A new model for in situ nitrogen incorporation into 4H-SiC during epitaxy[J]. Scientific Reports, 2017, 7: 43069.
[46] DAIGO Y, WATANABE T, ISHIGURO A, et al. Reduction of harmful effect due to by-product in CVD reactor for 4H-SiC epitaxy[C]//2020 International Symposium on Semiconductor Manufacturing (ISSM). December 15-16, 2020, Tokyo, Japan. IEEE, 2020: 1-4.