On the correlation between kink effect and effective mobility in InAlN/GaN HEMTs

This paper reports on the kink effect observed in InAlN/GaN high electron mobility transistors. Electrical characterizations were carried out to point out the influence of this phenomenon on transistor behaviour. It is demonstrated that the kink effect is directly correlated to shallow traps located under the conduction band. A model is proposed to highlight the influence of scattering effects on the effective mobility, permitting to describe accurately the locus of the so-called kink voltage for a gate bias close to the pinch-off voltage.