Enhanced thermal stability of Ga₂O₃ MOSFETs with nanocrystalline diamond field plate

The effect of the nanocrystalline diamond (NCD) field plate on the electrical and thermal characteristics of Ga₂O₃ MOSFETs is systematically investigated by electrothermal device simulation. The NCD field plate increases the drain current due to the suppression of the self-heating-effect-induced current drop in the saturation region for Ga₂O₃ MOSFETs. A >67 % reduction of maximum temperature rise can be achieved for the devices operating at P = 1.4 W/mm by using the NCD field plate. The peak temperature of the NCD field-plated Ga₂O₃ MOSFET decreases as the field plate length increases, while a thicker field plate support layer (>400 nm) almost eliminates the field plate effect. These results show that the NCD field plate can enhance the electrical and thermal characteristics of Ga₂O₃ MOSFETs, and provide insight into the thermal design of Ga₂O₃-based power devices.