Detailed Analysis on Determining Effective Dose for Various JTE-Based Edge Terminations Utilized on 4H-SiC Power Devices

Abstract

The article discusses the impact of thermal oxidation process conditions on the implanted junction-termination-extension (JTE) dose using various edge termination structures for 1700 V rated 4H-silicon carbide (4H-SiC) power devices. During the formation of gate oxide (Gox) via thermal oxidation, the surface of the SiC area is also consumed, resulting in a silicon dioxide layer. The surface consumption from the Gox process can significantly alter the blocking capabilities of the JTE-based edge termination structures due to a change in the ``effective'' dose. In addition, the fixed oxide charge and activation ratio can also fluctuate the charge in the JTE region. Therefore, all these factors should be considered when designing JTE-based edge terminations for 4H-SiC devices. Investigation of various edge termination structures such as single zone JTE (SZ-JTE), ring-assisted JTE (RA-JTE), multiple floating zone JTE (MFZ-JTE), Hybrid-JTE, and floating field rings (FFRs) allowed the identification of determining process steps. Detailed analysis of the effective JTE dose is reported by examining experimental and simulation results.