This paper presents the development of 1000 V, 30 A bipolar junction transistor (BJT) with high dc current gain in 4H-SiC. BJT devices with an active area of 3 3 mm 2 showed a forward on-current of 30 A, which corresponds to a current density of 333 A/cm 2 , at a forward voltage drop of 2 V. A common-emitter current gain of 40, along with a low specific on-resistance of 6.0 m cm 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 10 A is observed at CE = 2 V and = 600 mA at 225 C. The on-resistance increases to 22.5 m cm 2 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.Index Terms-4H-SiC, current gain, high-speed switching, power BJT.

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I n this paper, high performance, high voltage N P N bipolar junction transistors in 4H-Sic are presented for applications in low frequency (< 5 M H z ) power conversion systems. The power BJTs for low frequency switching applications were designed to block 1300 V and showed a specific onresistance of 8.0 mohm-emz, which outperforms all SIC power switching devices ever reported. Moreover, these transistors show a positive temperature coefticient in the on-resistance and a negative temperature coefficient io the current gain, which enable easy paralleling o f the devices.

The paper presents a study of the different aspects of the temperature dependent performance of a 4H-SiC epi-emitter Bipolar Junction Transistor particularly the low temperature performance. Some critical device physics related factors that affect the forward active performance of the device are explored and the device behavior is modeled up to 100K. We present for the first time the experimental low-temperature (down to 100K) performance of 4H-SiC epi-emitter BJTs and the determination of the temperature beyond which the current gain starts to increase with temperature. We have also corroborated these results with 2-dimensional device simulations.

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