垂直热壁CVD反应器中C/Si比对SiC高速同质外延生长的影响研究

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

摘要/Abstract

摘要： 本文结合计算流体力学(CFD)实验与模拟,对垂直热壁晶圆高速旋转CVD设备中SiC的同质外延生长机制进行研究,探讨了晶圆表面C/Si比对外延生长速率及载流子掺杂浓度的影响。结果表明晶圆表面上方碳原子对硅原子的摩尔比(记为有效C/Si比)与气体进口处C/Si比存在偏差。这一差异主要来自于气相传输过程中反应组分的重新分布,以及反应前驱体在气体进口处和/或热壁上的寄生沉积。研究了有效C/Si比对生长速率和掺杂浓度的影响,结果表明,外延生长速率、载流子掺杂浓度及其均匀性主要受到表面C/Si比而非进口处C/Si比的影响。通过优化生长条件,实现了高质量的6英寸(1英寸=2.54 cm)外延片生长,其厚度和掺杂浓度均匀性分别为1.15%和2.68%。在此基础上,获得了同等质量的8英寸SiC外延层,并实现了超过50 μm厚的SiC外延层快速生长。

关键词: 碳化硅, 同质外延, 化学气相沉积, C/Si比, CFD模拟仿真

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

中图分类号:

陈丹莹, 闫龙, 罗稼昊, 郑振宇, 姜勇, 张凯, 周宁, 廖宸梓, 郭世平. 垂直热壁CVD反应器中C/Si比对SiC高速同质外延生长的影响研究[J]. 人工晶体学报, 2025, 54(4): 569-580.

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.

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