Epi-ready SiC Substrates

Commercially viable silicon carbide device manufacturing processes depend on an ability to grow'low defect density epitaxial layers. Low defect density epitaxial layers start with pristine SiC substrate surfaces. Epi-ready pristine SiC surfaces are not commercially available. The results of this-programme should remedy this. In Phase I we will demonstrate a cost-effective, reproducible ex-situ surface preparation. ,Via a combination of mechanical and photoelectrochemical polishing methods for n-type SiC substrate, we will show that lower defect density epitaxial silicon carbide can be achieved. The new full wafer technique will remove surface and sub-surface damage introduced during sawing and polishing as well as chemical contamination that contribute to epitaxial layer defects. Reduction of epi-layer defects will lead to both improved device performance and increased manufacturing yields. In Phase II we will optimize surface preparation work for both 4H-SiC and 6H-SiC substrates based on in-house and customer epi results. In Phase III the protocol will be introduced into our substrate manufacturing process. The development of a commercially viable method for the surface preparation of SiC substrates will have a direct impact on removing unwanted surface morphological features likely to hinder device performance and yield. Our ability to produce epi-ready specular substrates will not only allow faster progress on the device research front but will also result in a highly desirable commercial product.