Performance of new self-aligned InP/InGaAs HBT's usingcrystallographically defined emitter contact technology

摘要

The performance of InP/InGaAs heterojunction bipolar transistors(HBT's), fabricated using a new crystallographically defined emittercontact technology, is investigated. In this technology, a newself-alignment process has been developed based on the crystallographicwet etching characteristics of an InP dummy emitter layer according tothe crystal orientation. The shape of the emitter electrode, which isdetermined by the crystallographically etched sidewall of the InP dummyemitter layer, is used for obtaining the desired contact spacing betweenthe emitter mesa and the base electrode. The fabricated HBT's show goodoverall device performance at high frequencies with a current gaincutoff frequency f_T of 94 GHz and a maximum oscillationfrequency f_max of 124 GHz. The microwave power performance ofthe device was also measured and characterized