A new functional AlGaAs/InGaAs/GaAs heterostructure-emitter and heterostructure-base transistor (HEHBT)

A new functional AlGaAs/InGaAs/GaAs heterostructure-emitter and heterostructure-base transistor (HEHBT) with a pseudomorphic base structure is presented. Due to the insertion of an InGaAs quantum well between the emitter-base (E-B) junctions, the valence band discontinuity can be enhanced and a high emitter injection efficiency may be achieved. In addition, an interesting S-shaped multiple negative differential resistance (MNDR) phenomenon is observed under the inverted operation mode. This may be attributed to an avalanche multiplication and sequential two-stage barrier lowering effect resulting from electron accumulation at the AlGaAs/GaAs heterointerface and InGaAs quantum well, respectively.