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

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.