A Study of 4H-SiC Semi-Superjunction Rectifiers for Practical Realisation

Abstract

This paper discusses the design and simulation of 4H-SiC semi-SJ structures producing results that are below the unipolar limit, whilst also ensuring practical and cost-effective realisation. The results demonstrate that a semi-SJ structure with a 10° sidewall angle increases the implantation window of the device by 45%, relative to the full-SJ, whilst maintaining a high VBD of ~2 kV and a low RON,SP. This design facilitates a wide implantation window with a reduced trench aspect ratio, significantly improving the practical realisation of the device. It also offers softer reverse recovery characteristics as a result of both the angled trench sidewall and the n-bottom assist layer (n‑BAL) which allows for the structure to be depleted gradually.