Degradation of Current Gain in SiC BJTs


The reduction in the current gain of SiC BJTs has been observed after operating the devices for as little as 15 minutes. It is accompanied by an increase in the on-resistance of the BJT. The origin of the current gain degradation in the BJTs is investigated. Two possible mechanisms, which may be simultaneously present in the device, are thought to be responsible: (a) increase in the surface recombination particularly in the region between the emitter and the base implant, and (b) bulk recombination in the base due to the generation and growth of stacking faults. Initial observation reveals the presence of stacking faults in the base-emitter region when the device is forward-biased. At the same time, minimizing the effects of recombination from the surface using improved passivation helped in the suppression of the current gain degradation in SiC BJTs.

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Agarwal, A., Krishnaswami, S., Richmond, J. et al. Degradation of Current Gain in SiC BJTs. MRS Online Proceedings Library 911, 1104 (2005).

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