Capacitance of abrupt one-sided InP/GaInAs heterojunctions

We demonstrate theoretically and experimentally that abrupt one-sided N-p+ heterojunctions behave like majority carrier diodes, in spite of the accumulation of minority carrier charge. Therefore, the diffusion capacitance should not be included in their equivalent circuit. An important result is that the base-emitter junction capacitance of abrupt heterojunction bipolar transistors can be precisely measured at high forward bias. An additional conclusion is that Schottky diodes can be replaced by abrupt heterojunctions, which have superior noise performance, and lower leakage current.