Reduction of the surface recombination current in InGaAs/InP pseudo-heterojunction bipolar transistors using a thin InP passivation layer

In an InGaAs/InP pseudo-heterojunction bipolar transistor (PHBT) with InP passivation, regions from the emitter mesa edge to the base contact are protected by a thin InP barrier layer. By using such a passivation, the surface recombination current is effectively suppressed. The DC current gain obtained for such a PHBT is as high as 455, compared to a maximum value of 240 for a normally passivated PHBT. The current gain is also found to be independent of the perimeter-to-area ratio of the emitter mesa as a result of the passivation.<
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