Experimental Demonstration of Pseudomorphic Heterojunction Bipolar Transistors with Cutoff Frequencies above 600 GHz

by Walid Hafez & Milton Feng Applied Physics Letters, 11 Apr 2005 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 0.4×6 µm² HBT achieves excellent _T values of 604 GHz (associated _MAX=246 GHz) at a collector current density of 16.8 mA/µm², with a dc gain of 65 and a breakdown voltage of BV_CEO=1.7 V. Read the article