Piezotronic probe modulates the piezoelectric-electric-thermal coupling field in GaN power electronics

Abstract

GaN high-electron-mobility-transistors (HEMTs) exhibit superior high-power and high-frequency characteristics; however, they generate a substantial amount of heat during operation. As quantum piezotronic devices, GaN HEMTs are of particular interest due to their strong coupling processes between piezoelectric, electrical and thermal fields, which are still being explored. For the first time, we built a theoretical framework combining piezotronics with an electrothermal model to reveal the thermal spatial distribution and temporal evolution of GaN HEMTs. Advanced infrared thermography shows that the heat source is localized near the gate in the fabricated GaN HEMTs, which aligns with our theoretical model. The dynamic temperature characteristics indicate that the substrate layer contributes to the main thermal resistance and capacitance. Notably, by introducing an external stress, piezoelectric polarization can act as a probe to locally modulate the thermal fields. A 10.1% decrease in temperature rise is realized during the dynamic modulation process, which further confirms the accuracy of the model. This work deepens the understanding and cognition of piezoelectric-electric-thermal coupling processes and offers a novel thermal management strategy for GaN HEMT devices.