Characteristics of Crystal Defects in AlGaN/GaN HEMTs at Low Temperature

In this study, we observed changes in the characteristics of the crystal defects in the crystal layers forming aluminum gallium nitride/gallium nitride high electron mobility transistors at low temperatures. A kink phenomenon was observed in the IV characteristics as the temperature decreased. Moreover, the current gain increased as the temperature decreased. Furthermore, the parasitic capacitance showed a similar temperature characteristic. The mode in which crystal defects capture carriers can be explained by a switch in the transport phenomenon from the induction of carriers to crystal defects triggered by carrier capture, rather than by two-dimensional electron gas depletion.