GAALAS/GAINP/GAAS PASSIVATED HETEROJUNCTION BIPOLAR-TRANSISTORS FOR HIGH BIT-RATE OPTICAL COMMUNICATIONS

We present a new Passivated Heterojunction Bipolar Transistor structure which yields high performance devices with a very simple processing technology. A thin n-type GaInP layer is inserted between the base layer and the GaA1As emitter layer and allows, with the same processing step, the passivation of the base layer and the selective etching of the emitter layers. The new structure also gives a low and reproducible p-type ohmic contact resistivity. High bit rate laser driver circuits have been processed using this new structure and are operating at 7 Gbit/s.