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

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 3×3 mm² showed a forward on-current of 30 A, which corresponds to a current density of 333 A/cm², at a forward voltage drop of 2 V. A common-emitter current gain of 40, along with a low specific on-resistance of 6.0mΩ·cm² 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_CE=2 V and I_B=600 mA at 225°C. The on-resistance increases to 22.5 mΩ·cm² at higher temperatures, while the dc current gain decreases to 30 at 275°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.