High-Temperature Static and Dynamic Reliability Study of 4H-SiC Vertical-Channel JFETs for High-Power System Applications

摘要

In this work we report the most recent high-temperature long-term reliability results of the 600 V/14 A, 4H-SiC vertical-channel junction field-effect transistors (VJFETs). Two groups (A and B) devices were subjected to different thermal and electrical stresses. One device (Group A) reached 12,000 hours of continuous switching without a single failure. Four devices in Group A were thermally stressed at 250 °C over 4,670 hours in air, for which standard deviation of the specific on-resistance (R_ONSP) in linear region at gate bias (Vgs) of 3 V were < 4.1% throughout the entire duration time. The off-state characteristics were evaluated by high temperature reverse bias (HTRB) tests. Three devices (Group A) were biased at 50% rated BV_(DS) at 250 °C for 2,278 hours. A higher reverse bias at 80 % rated BVds was then applied to 14 devices (group B) at 200 °C for 1,000 hours. Variations of the leakage current were negligible throughout the entire HTRB test for all tested devices.