Experimental demonstration of pseudomorphic heterojunction bipolar transistors with cutoff frequencies above 600 GHz

摘要

Pseudomorphic InP/InGaAs heterojunction bipolar transistors (PHBTs) using a compositionally graded collector (10% indium grading) and graded base (6% indium grading) to reduce the transit time of the device are reported. A 0.4 X 6 μm~2 HBT achieves excellent f_T values of 604 GHz (associated f_(MAX) = 246 GHz) at a collector current density of 16.8 mA/μm~2, with a dc gain of 65 and a breakdown voltage of BV_(CEO) =1.7 V.