Multiple negative-differential-resistance (NDR) of InGaP/GaAs heterostructure-emitter bipolar transistor (HEBT)

An interesting multiple S-shaped negative-differential-resistance (NDR) phenomenon is observed for an InGaP/GaAs heterostructure-emitter bipolar transistor (HEBT) under the inverted operation mode. This behavior results from a sequential avalanche multiplication and two-stage barrier lowering effect. The two-stage barrier lowering effect is assumed to be caused by the high valence-band-discontinuity (/spl Delta/E/sub v/) to conduction-band-discontinuity (/spl Delta/E/sub c/) ratio at InGaP/GaAs heterointerface which gives holes and electrons accumulation effect successively. Under normal operation mode, a typical common-emitter current gain of 60 is obtained at collector current density of 400 A/cm/sup 2/ for the studied HEBT without emitter-edge thinning structure. Consequently, the controlled switching and transistor performances provide a promise of the studied device for circuit applications.