PSEUDOMORPHIC ALINPINP HETEROJUNCTION BIPOLAR-TRANSISTORS

Novel InP-based heterojunction bipolar transistors (HBTs) using an AlI nP pseudomorphic emitter, together with an InP base and collector, hav e been fabricated. By using InP as both base and collector. the advant ages of high electron velocity and high breakdown field of InP collect ors are obtained without the problem associated with the energy barrie r between the more standard InGaAs/InP base and collector heterojuncti on. Epitaxial layers were grown by gas-source molecular beam epitaxy ( GSMBE). The 200 Angstrom pseudomorphic emitter has an aluminium fracti on of 15%, sufficiently suppressing hole injection from the base. The DC gain for 40 x 40 mu m(2) devices reached 18. The breakdown voltage BVCEO of 10V is an improvement over devices with InGaAs base and colle ctor layers.