Extrinsic Base Surface Recombination Current in Surface-Passivated InGaP/GaAs Heterojunction Bipolar Transistors

Abstract

Recombination currents at the emitter mesa periphery of InGaP/GaAs heterojunction bipolar transistors (HBTs) with and without extrinsic base surface passivation layers are evaluated and compared. The obtained ideality factor for the extrinsic base surface recombination curtent in InGaP/GaAs HBTs with the surface passivation layer is 1.6, which is considerably larger than the near-unity value for the HBTs without the surface passivation layer. This indicates a difference in the surface recombination mechanism between passivated and unpassivated InGaP/GaAs HBTs.