Physical Insights Into the Kink Effects in GaN Power HEMTs

In this work, a well-calibrated computational framework is used to study the kink effect and explain the physical mechanisms responsible for it. Impact ionization model and traps induced by C-doping in the GaN buffer are found to be critical in reproducing the kink effect. Substrate bias-dependent analysis and detailed computations reveal an interplay of different trapping mechanisms in the GaN buffer and impact ionizationgenerated holes in determining the kink effect. The estimation of exact physical mechanisms responsible for kink, provided through this work, will enable device designers to avoid kink by taking appropriate measures during GaN power HEMT design.