Epitaxial Growth on 2° Off-axis 4H SiC Substrates With Addition of HC1

摘要

Epitaxial growth on 3-in, 2° off-axis 4H SiC substrates has been conducted in a horizontal hot-wall CVD reactor with HC1 addition. The thickness of the epiwafers ranges from 3 μm to 11 μm and the growth rate is 7 - 7.5 μm/h. Although a rougher surface and a higher triangular defect density is observed using the standard process for 4° growth, an improved process has resulted in reduced triangular defect density down to around 4 cm~(-2) and a smoother surface with the roughness of 1.1 nm for a 3.7 μm thick epiwafer. Most interestingly, the basal plane dislocation density in the 2° off-axis epiwafers has been reduced to non-detectable levels, as confirmed by both the non-destructive UVPL mapping technique and the molten KOH etching on 2° epiwafers with thickness of around 10 μm.