High Current and Low Turn-On Voltage InAlAs/InGaAsSb/InGaAs Heterojunction Bipolar Transistor

This study investigates the DC characteristics of a heterojunction bipolar transistor (HBT) with a quaternary InGaAsSb base, grown by solid-source molecular beam epitaxy (MBE). The novel In_0.52Al_0.48As/In_xGa_1-xAs_1-ySb_y HBT has a lower base/emitter (B/E) junction turn-on voltage, a lower V_CE.offset voltage and a greater junction ideality factor than conventional In_0.52Al_0.48As/In_0.53Ga_0.47As single HBT structures. The quaternary In_xGa_1-xAs_1-ySb_y base provides a type-I B/E junction and a type-II base/collector (B/C) junction, suggesting that the InGaAsSb base HBT has great potential for low-power and high-speed applications.