Scaling of Chlorosilane SiC CVD to Multi-Wafer Epitaxy System

Abstract

A SiC epitaxy process based on chlorosilane/propane chemistry has been successfully transferred from a single-wafer R&D system to a multi-wafer CVD reactor. The optimized process results in very smooth epi surface (RMS~0.24nm) and minimum surface pits (less than 0.5/cm2). Both n-type and p-type doping in a wide range are demonstrated using nitrogen and aluminum, respectively. The high performance benchmarks for thickness uniformity (intra-wafer variation <1% and inter-wafer variation <1%) and doping uniformity (intra-wafer variation <6% and inter-wafer variation <3%) are achieved on 5 x 3-inch wafers. The carrier lifetime in these epilayers measured by μ-PCD is over 5 μs, the longest value reported so far for SiC epitaxial wafers.