Effects of Temperature and Bias Voltage on Electron Transport Properties in GaN High-Electron-Mobility Transistors

In this study, we investigated the effects of temperature and bias voltage on the electron transport properties of AlGaN/GaN high-electron-mobility transistors in the saturation region using a turn-on delay time. A sine wave signal was used to accurately acquire the delay time between the gate-source voltage and drain-source current signal of the device at temperatures ranging from
$30\mathbf { \mathtt {^\circ }}\text{C}$
to
$180\mathbf {\mathtt {^\circ }}\text{C}$
under operating conditions. With this method, we illustrated a non-monotonic relationship between the temperature and the delay time, which was closely related to the effect of temperature on saturation drift velocity and charge trapping. In addition, it suggested that the delay time increased with increasing drain-source voltage, which was ascribed to the effect of charge trapping. The validity of the proposed results has been thoroughly verified with similar phenomena on two samples. The results may be useful for further study on the electron transport of GaN HEMTs under high temperature and voltages.