Growth of SiC bulk crystals for application in power electronic devices - process design, 2D and 3D X-ray in situ visualization and advanced doping

摘要

Silicon carbide single crystals have become widely used as substrates for power electronic devices like diodes and electronic switches. Today, 4inch and 6inch wafer diameters are commercially available which are processed from vapor grown crystals. The state of the art physical vapor transport method may be called mature. Nevertheless, low defect density and uniform doping are still topics which can be further improved by current research and development of more sophisticated processes and process control. The aim of the paper is to review the physical vapor transport growth method as applied today. Special emphasis will be put on currently less advanced in situ growth monitoring tools based on 2D and 3D X-ray imaging that could be a tool for production monitoring. These techniques allow a precise determination of the crystal and source material evolution. Another topic will be the processing of highly conductive p-type 4H-SiC which is of particular interest for power electronic switches.