Reduction of the Surface Recombination Current in InGaAs/InP Pseudo-Heterojunction Bipolar Transistors Using a Thin InP Passivation Layer.

We have demonstrated an InGaAs/InP pseudo-heterojunction bipolar transistor (PHBT) with InP passivation. In this scheme, the 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 normal 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.