DC and 1/f noise characteristics of InGaP/InGaAsN/GaAs double heterojunction bipolar transistors

Abstract

A novel quaternary material of InGaAsN has been proposed as a base layer for GaAs-based double heterojunction bipolar transistors (DHBTs). By utilizing InGaAs as a base material, a lower band gap energy of the base layer in heterojunction bipolar transistors (HBTs) followed by a smaller turn-on voltage can be achieved. The 1/f noise characteristics of HBTs with an InGaAs base layer also show great improvement. Moreover, a smaller band gap base material of InGaAsN latticed-matched to a GaAs substrate can be obtained by incorporating suitable amounts of indium (In) and nitrogen (N) into GaAs base material, and thus enhance turn-on voltage reduction. In this study, dc and flicker noise characteristics of InGaAsN DHBTs are investigated by comparing GaAs and InGaAs DHBTs. The experimental results show that the 1/f noise has been found to depend on Ib as Iγb, where 1.95 < γ < 2.04 for the InGaP/InGaAsN DHBTs with high current gains (β ∼ 60). The 1/f noise of the InGaAsN sample is one order lower than that of the GaAs sample.