Journal of Crystal Growth, Vol.268, No.3-4, 410-414, 2004
A comparative study of metamorphic InP/InGaAs heterojunction bipolar transistors (MHBTs) grown by gas and solid source molecular beam epitaxy (MBE)
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 x 20 mum(2) and base Be doping concentration of 2 x 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 (beta X 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 (BVceo xf(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. (C) 2004 Elsevier B.V. All rights reserved.