Observation of Kink effect in Carbon-doped GaN-on-Si HEMTs for Power Applications

For the first time, kink effect is observed in output characteristics of carbon-doped GaN-on-Si HEMT with gate length of 2.5 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \mathbf{m}$</tex>. This kink arises from the hot electron-assisted de-trapping mechanism and is affected by substrate bias. Experiments suggest that a negative potential is induced in the C-doped GaN buffer due to charge trapping, leading to increased probability of hot electron-assisted de-trapping due to the peak electric field in the channel. The effect of temperature on the kink reveals a non-monotonic behavior for both <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{DS,kink}$</tex> and kink amplitude.