Over-220-GHz-f/sub T/-and-f/sub max/ InP/InGaAs double-heterojunction bipolar transistors with a new hexagonal-shaped emitter

Abstract

Superior high-frequency characteristics with peak f/sub T/ of 228 GHz and f/sub max/ of 227 GHz are demonstrated for self-aligned InP/InGaAs DHBTs with a novel collector structure and a new hexagonal emitter geometry. These improvements in f/sub T/ and f/sub max/ are due to the thickness optimization of the base and collector layers and the reduction of parasitic base resistance and base/collector capacitance through the use of the new emitter geometry.