Impact of Temperature on Threshold Voltage Drift in AlN/GaN MIS-HEMTs

This study investigates the temperature-dependent threshold voltage behavior in AlN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) fabricated on a silicon substrate with stacked gate dielectrics, employing both experimental measurements and analytical modeling to provide a comprehensive understanding. The relationship between threshold voltage and temperature is quantitatively analyzed using an analytical expression that incorporates key parameters, such as the barrier height and the density of interfacial negative charge. Experimental measurements reveal that the threshold voltage exhibits a negative drift with increasing temperature, while the barrier height shows a positive shift. By calculating the variation in interface trap charge density, we identify that the negative drift in threshold voltage is primarily due to the release of electrons from interface traps at elevated temperatures. These findings provide valuable guidance for optimizing device performance in temperature-sensitive applications.