Forward transit delay in In/sub 0.53/Ga/sub 0.47/As heterojunction bipolar transistors with nonequilibrium electron transpor

Abstract

The microwave performance of high speed InP/In 0.53 Ga 0.47 As Heterojunction bipolar transistors is measured in the temperature range 55 K≤T≤340 K. The extrinsic unity currents gain cut-off frequency is f T =130 GHz at temperature T=340 K increasing to f T =300 GHz at T=55 K. The intrinsic emitter-collector forward delay decreases with decreasing temperature from T F =0.5 ps at T=340 K to a saturated value of T F =0.28 ps for temperatures T≤150 K. Such behavior may only be explained by the presence of non-equilibrium electron transport in the base and collector of the device