600-V Symmetrical Bi-Directional Power Switching Using SiC Vertical-Channel JFETs with Reliable Edge Termination

Abstract

Numerous high-voltage applications require symmetrical bi-directional power flow control and protection circuitry. While mechanical contactors and circuit breakers provide bi-directional fault protection, they have slow actuation and suffer severe degradation during repeated fault isolation. The normally-on (N-ON) SiC vertical-channel Junction-Field-Effect-Transistor (VJFET) is an efficient solution for bi-directional circuit-breaker applications due to its low conduction/switching losses, +500°C operational capability, ON-state match of the no-fault operating mode of the system, efficient gate-drive operation under unipolar biasing, and majority carrier device scalability. Efficient 600-V/10-A symmetrical bi-directional power flow was demonstrated using 0.1-cm2 1200-V rated N-ON VJFETs with a gate driver applying 0-V and -34 V gate biases during the ON and OFF states, respectively. A self-aligned trenched guard-ring structure provides reliable edge termination.