Temperature rise detection in GaN high-electron-mobility transistors via gate-drain Schottky junction forward-conduction voltages

An electrical measurement method for the junction temperature and thermal resistance of GaN high-electron-mobility transistors (HEMTs) is discussed. It is based on the forward voltage drop across the gate-drain Schottky diode. During measurement of this temperature-sensitive parameter, the source is left floating while the drain is grounded. Previous studies have shown that the hot spot in GaN HEMTs is near the gate side, close to the drain. The forward voltage drop across the gate-drain diode yields higher and more consistent temperatures relative to those using the forward voltage drop across the gate-source Schottky diode. This method could potentially provide more accurate data for thermal management and reliability analyses of GaN-based HEMTs. The maximum temperature of the sample was 44.8 °C on the grate-drain side and approximately 40.5 °C on the gate-source side when the sample exhibited 3.44-W thermal power consumption for 1 min. Hence, the proposed method is practical and instructive.