Resonant tunneling bipolar transistors using InAlAs/InGaAs heterostructures

Resonant tunneling bipolar transistors (RBTs) using InAlAs/InGaAs heterostructures were fabricated. These devices are bipolar transistors which use a resonant tunneling barrier as a minority-carrier injector. The RBT exhibits a collector current peak as a function of the base-emitter voltage at room temperature. The peak-to-valley ratio of the collector current is 3.5, and the peak collector current density is 5.7×104 A/cm2. The common-emitter current gain reaches a value of 24. These InAlAs/InGaAs RBTs characteristics are much better than those of AlGaAs/GaAs RBTs. We measured the microwave characteristics of the InAlAs/InGaAs RBT at room temperature, and obtained a cutoff frequency of 12.4 GHz. An equivalent circuit analysis and device simulation yielded an estimated resonant tunneling barrier response time of 1.4 ps.