InP/InGaAs SHBTs with 75 nm collector and f T >500 GHz

Abstract
InP/InGaAs single heterojunction bipolar transistors (SHBTs) are fabricated exhibiting current-gain cutoff frequencies, fT of 509 GHz. The 0.35×12 µm2 devices consist of a 25 nm graded base and a 75 nm collector, have a breakdown BVCEO of 2.7 V, and operate at current densities above 1100 kA/cm2. This work demonstrates clear progress toward a THz transistor.