A new physical model for the kink effect on InAlAs/InGaAs HEMTs

New measurements providing direct evidence linking the kink effect and impact ionization in InAlAs/InGaAs HEMTs are reported. Current kink models are not consistent with our findings. We propose a new mechanism, barrier-induced hole pile-up at the source, to explain the kink. The new model is shown to be consistent with both room temperature and low temperature measurements. These results allow formulation of a simple equivalent circuit model of the kink.