InGaAs/InP double-heterostructure bipolar transistors with near-ideal β versus ICcharacteristic

Abstract

InGaAs/InP double-heterostructure bipolar transistors (DHBT's) with current gain β ∼ 630 have been realized using gas-source molecular beam epitaxy (GSMBE). These devices exhibit near-ideal β versus I C characteristic (i.e., β independent of I C ) with a small-signal gain h_{fe} \sim 180 at I_{C} \sim 2 nA. In comparison, we find \beta \sim I_{C}^{0.5} for a high-quality AlGaAs/GaAs HBT grown by OMCVD. The higher emitter injection efficiency at low collector current levels found in the InGaAs/InP DHBT is due to at least a factor 100 smaller surface recombination current.