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4°偏轴SiC衬底上生长的外延薄膜容易出现台阶形貌,外延薄膜表面的台阶形貌对后续制作的器件性能有着一定的影响。主要研究了进气端C/Si比及生长前刻蚀工艺对4°偏轴衬底外延的影响。采用外延生长前的氢气刻蚀工艺,结合掺杂浓度缓变的缓冲层设计,在4°偏轴的SiC衬底上制得了表面无台阶形貌的SiC SBD结构外延材料。利用优化工艺生长的4°偏轴衬底上的SBD结构外延材料目前已经全面应用于600～1 700V SBD器件的研制。
The epitaxial films grown on 4 ° off-axis SiC substrates tend to have a step-like morphology, and the surface topography of the epitaxial films has an impact on the performance of the fabricated devices. The effects of inlet C / Si ratio and pre-growth etching on the epitaxial growth of 4 ° off-axis substrate are mainly studied. Hydrogen etching before epitaxial growth and buffer layer design with slowly changing doping concentration were used to fabricate SiC SBD epitaxial materials with no surface topography on the 4 ° off-axis SiC substrate. The SBD structure epitaxial material grown on the 4 ° off-axis substrate using the optimized process has been fully applied to the development of 600 ~ 1 700V SBD devices.