High Frequency InGaP/GaAs Planar Heterojunction Bipolar Transistors

The present paper reports on high frequency In0.49Ga0.51P/GaAs HBTs and high speed lightwave communication circuits using a novel planar self-aligned fabrication process based on chemical beam epitaxial (CBE) selective regrowtlh of both the extrinsic base and subcollector layers. Using this process, a current gain of 43 and cutoff frequencies of 50 and 70 GHz for fT and fMAX respectively, have been achieved for a 10×3 ¿m² emitter-base junction area device. A 7 Gbit/s decision circuit (DEC) and a 17 GHz dynamic frequency divider were successfully fabricated using planar HBTs.