基于正交实验的100mm 4°偏轴SiC衬底外延均匀性研究

Uniformity Control for 100 mm 4° SiC Epilayers Based on Orthogonal Experiment

采用行星热壁式SiC外延炉对100 mm 4°偏轴4H-SiC衬底外延工艺进行了研究。分析了氢气预刻蚀工艺对4°偏轴衬底外延材料表面形貌的影响。采用双指标正交实验,通过极差分析的方法研究了C/Si比、Cl/Si比、主氢流量、生长温度、三路气体比等工艺参数对SiC外延厚度和掺杂浓度均匀性指标影响的主次顺序,并给出了优化的外延参数。采用该工艺条件制得的无台阶聚集形貌的SiC外延片片内厚度均匀性和浓度均匀性分别是1.23%和3.32%。

In this paper, the epitaxial process for 100 mm （4 inch） 4°off-axis 4H-SiC （0001） substrates using a planetary hot-wall reactor was studied. The influence of in-situ hydrogen etching process on the surface morphology of epitaxial layers has been investigated. A double index orthogonal experiment was developed to confirm the primary factor for the doping concentration and thickness uniformity including C/Si ratio, Cl/Si ratio, the main hydrogen flow, growth temperature, and three-way hydrogen gas ratio, meanwhile, the optimized epitaxial parameters were also obtained. Under the optimized conditions, the intra-wafer thickness uniformily is 1.23 %, and the concentration uniformily is 3.32%.