1000-V, 30-A 4H-SiC BJTs with high current gain

Abstract

This paper presents the development of 1000 V, 30A bipolar junction transistor (BJT) with high dc current gain in 4H-SiC. BJT devices with an active area of 3/spl times/3 mm/sup 2/ showed a forward on-current of 30 A, which corresponds to a current density of 333 A/cm/sup 2/, at a forward voltage drop of 2 V. A common-emitter current gain of 40, along with a low specific on-resistance of 6.0m/spl Omega//spl middot/cm/sup 2/ was observed at room temperature. These results show significant improvement over state-of-the-art. High temperature current-voltage characteristics were also performed on the large-area bipolar junction transistor device. A collector current of 10A is observed at V/sub CE/=2 V and I/sub B/=600 mA at 225/spl deg/C. The on-resistance increases to 22.5 m/spl Omega//spl middot/cm/sup 2/ at higher temperatures, while the dc current gain decreases to 30 at 275/spl deg/C. A sharp avalanche behavior was observed at a collector voltage of 1000 V. Inductive switching measurements at room temperature with a power supply voltage of 500 V show fast switching with a turn-off time of about 60 ns and a turn-on time of 32 ns, which is a result of the low resistance in the base.