Pseudomorphic InP/InGaAs Heterojunction Bipolar Transistors (PHBTs) Experimentally Demonstrating fT = 765 GHz at 25°C Increasing to fT = 845 GHz at -55°C

Abstract

Pseudomorphic InP HBTs (PHBTs) with a vertically scaled design implementing a 12.5 nm base and 55 nm collector exhibit record current gain cutoff frequency performance of f_T=765 GHz when measured at 25°C. When cooled to -55°C, f_T improves more than 10% to f_T=845 GHz due to enhanced electron transport and reduced parasitic charging delays as determined by small signal equivalent circuit parameter extraction. Peak performance current density J_c=18.7 mA/μm² and BV_CEO =1.65 V