HETEROSTRUCTURE-EMITTER AND PSEUDOMORPHIC BASE TRANSISTOR (HEPBT) WITH A GRADED ALXGA1-XAS CONFINEMENT LAYER

In this paper, we will demonstrate a new heterostructure-emitter and p seudomorphic base transistor (HEPBT) with a graded AlxGa1-xAs confinem ent layer. The device studied takes the advantages of the heterostruct ure-emitter bipolar transistor, the graded heterojunction bipolar tran sistor (HBT), and an AlGaAs/GaAs HBT with an InGaAs base layer simulta neously. Owing to the presence of the GaAs emitter and graded AlxGa1-x As confinement layer, a low offset voltage of 100 mV is obtained. Also , attributed tu the insertion of a InGaAs quantum well, a high emitter efficiency yielding the high common-emitter current gain of 120 is ac hieved. Consequently, the HEPBT studied shows a promise for circuit ap plications. (C) 1997 Elsevier Science S.A.