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 (MN DR) switching behaviors based on the InGaP/GaAs heterostructure-emitter bip olar transistor (HEBT) and InGaAlAs/InP heterojunction bipolar transistor ( HBT) structures. The devices act like conventional HBTs under forward opera tion mode. The proposed HEBTs show lower offset voltage due to the correct design of the emitter thickness. On the other hand, MNDR phenomena resultin g from avalanche multiplication, confinement effects and the potential redi stribution process are observed under inverted operation mode for both devi ces. in addition, three-terminal NDR characteristics are investigated under the applied base current I-B. Moreover, for the InGaAlAs/InP HBT, anomalou s 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) betwe en the base and collector layers. (C) 2001 Academic Press.