A physical model for the kink effect in InAlAs/InGaAs HEMTs

We present a new model for the the kink effect in InAlAs/InGaAs HEMTs. The model suggests that the kink is due to a threshold voltage shift which arises from a hole pile-up in the extrinsic source and an ensuing charging of the surface and/or the buffer-substrate interface. The model captures many of the observed behaviors of the kink, including the kink´s dependence on bias, time, temperature, illumination, and device structure. Using the model, we have developed a simple equivalent circuit, which reproduced well the kink´s dc characteristics, its time evolution in the nanosecond range, and its dependence on illumination