High-performance AlGaInP tunneling heterostructure-emitter bipolar transistor

•An AlGaInP tunneling heterostructure-emitter bipolar transistor is demonstrated.•A n-AlGaInP tunneling layer and a n-GaAs layer forms heterostructure emitter.•The heterostructure emitter is employed to decrease collector–emitter offset voltage.•Small hole transmission coefficient across the AlGaInP tunneling layer.•Most of holes injecting from base will be blocked at AlGaInP/GaAs heterojunction.

In this paper, a high-performance heterostructure-emitter bipolar transistor employing an AlGaInP quaternary compound tunneling layer is fabricated and demonstrated. In the studied device, a 50 Å n-AlGaInP tunneling emitter layer together with a 200 Å n-GaAs layer forms the heterostructure emitter to decrease the collector–emitter offset voltage. On the other hand, due to the relatively large valence band discontinuity (∼0.4 eV) at AlGaInP/GaAs heterojunction and the small hole transmission coefficient across the AlGaInP tunneling layer, most of holes injecting from base to emitter will be blocked at AlGaInP/GaAs heterojunction and then high collector current and current gain are achieved. The experimental results exhibit a large collector current of 92 mA, a large current gain of 446, and a relatively low offset voltage of only 45 mV, respectively. Furthermore, a large current-gain cutoff frequency ft up to 63.7 GHz is obtained for the device with a thin tunneling layer.