Dynamic characteristics of high voltage 4H-SiC vertical JFETs

Abstract

We have developed a novel structure for a fully implanted, normally-on vertical junction field effect transistor (VJFET) and fabricated prototypes with blocking voltages between 600 and 1000 V. Mounting the SiC VJFET together with a 50 V Si MOSFET on a DCB substrate in a cascode circuit, we obtain a normally-off high voltage switch. The specific on-resistance of the VJFET was sufficiently low, in the range of 18 to 40 m/spl Omega/cm/sup 2/, for various blocking voltages. The dynamic behaviour shows turn-off times between 50 ns and 2 /spl mu/s due to the RC-product of two different p-gate networks.