Study of the multiple-negative-differential-resistance (MNDR) switching behaviors based on heterojunction bipolar transistor (HBT) structures

In this paper, we demonstrate multiple-negative-differential-resistance (MNDR) switching behaviors based on the InGaP/GaAs heterostructure-emitter bipolar transistor (HEBT) and InGaAlAs/InP heterojunction bipolar transistor (HBT) structures. The devices act like conventional HBTs under forward operation mode. The proposed HEBTs show lower offset voltage due to the correct design of the emitter thickness. On the other hand, MNDR phenomena resulting from avalanche multiplication, confinement effects and the potential redistribution process are observed under inverted operation mode for both devices. in addition, three-terminal NDR characteristics are investigated under the applied base current I-B. Moreover, for the InGaAlAs/InP HBT, anomalous multiple-route and multiple-step current-voltage (I-V) characteristics at 77 K are observed due to the insertion of a InGaAs quantum well (QW) between the base and collector layers. (C) 2001 Academic Press.