EVALUATION OF MOLECULAR-BEAM EPITAXIALLY GROWN ALGAAS GAAS HETEROJUNCTIONS FOR BIPOLAR-TRANSISTOR WITH INGAAS EMITTER CONTACT LAYER/

Molecular beam epitaxially grown AlGaAs/GaAs heterojunctions were char acterized by isothermal capacitance transient spectroscopy to study th e performance of bipolar transistors with lattice-mismatched InGaAs em itter contact layer, A deep level around 0.48 eV is found to be a reco mbination center in the N-AlGaAs/p(+)-GaAs junction which might be ind uced by oxygen. Anomalous signals are also observed under an isotherma l condition where the edge of the depletion layer reaches the graded I nGaAs/AlGaAs heterointerface. Two electron traps with activation energ ies of 0.26 and 0.62 eV are identified as dominant factors. (C) 1996 A merican Institute of Physics.