A physical model for the kink effect in InAlAs/InGaAs HEMT's

We present a new model for the the kink effect in In-AlAs/InGaAs HEMT's, Th e model suggests that the kink is due to a threshold voltage shift which ar ises 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 the 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 de characteristics, its time evolution in the nanosecond range, and its dependence on illumination.