InGaAs/AlAs/InGaAsP resonant tunneling bipolar transistors grown by chemical beam epitaxy

Resonant tunneling bipolar transistors (RTBT´s) have been systematically studied using chemical beam epitaxy (CBE) for the first time. The RTBT structure studied is a InP-based transistor, consisting of single or multiple AlAs/In_0.75Ga_0.25As/AlAs RTD´s in the emitter layer of a conventional heterojunction bipolar transistor (HBT) and an InGaAs or InGaAsP collector layer. Using the InGaAsP collector layer, the RTBT showed an improvement of breakdown voltage from 4 V to 10 V. The averaged DC β´s are around 10 and 20 at 300 K and 77 K, respectively. In the transfer I-V characteristics, the RTBT showed 1 to 4 negative differential transconductance (NDT) peaks with peak-to-valley current ratios of 1.5 to 5.28 at 300 K. Using such NDT peaks, several RTBT digital functions were demonstrated at room temperature, including a frequency multiplier and exclusive NOR gate