Breakdown Voltage Characteristics of FLR-assisted SiC-SBD Formed by Aluminum Metal Junction Edge Termination

摘要

This paper demonstrates the breakdown voltage characteristics of different edge termination structures including aluminum (Al)-deposited guard ring and Al-deposited guard ring-assisted field limiting ring (FLR) for a 4H silicon carbide (SiC) Schottky barrier diode (SBD). In order to investigate the application feasibility of the Al-deposited junction termination to a high breakdown voltage SiC-SBD, two types of SiC-SBDs are fabricated using conventional photolithography, electron beam evaporation, and thermal treatment techniques without ion implantation and thermal oxidation procedures. The breakdown voltage characteristics of the SiC-SBDs are significantly dependent on the Al-deposited edge termination. The SiC-SBD without the Al-deposited edge termination shows less than 250 V breakdown voltage, while the Al-deposited guard ring and Al-deposited guard ring-assisted FLR structures show roughly 700 V and 1200 V breakdown voltages, respectively. The prominent improvement in the breakdown voltage characteristics is attributed to the electric field lowering at the Schottky contact edge by the Al deposition edge termination.