Multi-Wafer VPE Growth of Highly Uniform SiC Epitaxial Layers

Abstract

A multi-wafer silicon carbide vapor phase epitaxy reactor is employed that features full planetary motion and is capable of high quality epitaxy on seven, two-inch diameter substrates. We are currently performing preproduction growths of static induction transistor (SIT) and metal semiconductor field effect transistor (MESFET) active layers. On a 2-inch diameter substrate, layer uniformity is typically ±5% (standard deviation/mean) for both dopant concentration and layer thickness (for 1 3/8-inch substrates, layer uniformity is around ±3%). For the seven wafers within a run, interwafer uniformity has been dramatically improved to approximately ±8% for dopant concentration and ±3% for layer thickness. Process control charts will be presented which exhibit that interrun (run-to-run) variation in both thickness and doping can be kept within ±10% of the desired values.