AN IMPROVED IN0.5GA0.5P GAAS DOUBLE HETEROSTRUCTURE-EMITTER BIPOLAR-TRANSISTOR USING EMITTER EDGE-THINNING TECHNIQUE/

An improved In0.5Ga0.5P/GaAs double heterostructure-emitter bipolar tr ansistor (DHEBT) has been fabricated by low-pressure metalorganic chem ical vapor deposition (LP-MOCVD). The 100 Angstrom undoped GaAs spacer s grown on both sides of the base are used to improve the recombinatio n of p-n interface and to increase the common-emitter current gain. Th e emitter edge-thinning technique is used to reduce the surface recomb ination current and improve the current gain. A current gain of 180 wi th an offset voltage as low as 60 mV are achieved. Meanwhile, Gummel p lot is shown to understand the composition of collector and base curre nts.