A comparative study of metamorphic InP/InGaAs heterojunction bipolar transistors (MHBTs) grown by gas and solid source molecular beam epitaxy (MBE)

Abstract

A comparative study of InP-based metamorphic heterojunction bipolar transistors (MHBTs) grown by gas and solid-source molecular beam epitaxy techniques is presented. The DC and RF performance measured on the devices with an emitter size of 1.6×20 μm 2 and base Be doping concentration of 2×10 19 cm −3 are summarized. The figures of merit for these two MHBTs such as the product of DC current gain and maximum oscillation frequency (ß× f max) which are governed by base quality and the doping concentration, and the product of the common emitter breakdown voltage and the unity current gain cut-off frequency (BV ceo× f T) which are related to the thickness variation are found to be similar. This suggests that both the solid-source and the gas-source MBE techniques may offer similar material quality, and hence higher device performances could be achieved by proper optimization of the material growth conditions.