Active Thermal Management of GaN-on-SiC HEMT With Embedded Microfluidic Cooling

In recent decades, gallium nitride (GaN) high-electron-mobility transistor (HEMT) has become increasingly popular for microwave applications due to its wide bandgap and high saturated electron velocity. However, self-heating inhibits the improvement of its electrical characteristics and reduces device reliability. In this study, a thermoelectric analysis based on embedded microfluidic cooling is performed. By embedding the microchannel into the silicon carbide (SiC) substrate, the coolant can be introduced directly to realize active near junction cooling. According to the thermal resistance model, embedded cooling shortens the thermal path and enhances the capacity of heat convection, and the improvement in the HEMT output characteristics is also verified experimentally. The saturation current increases by 19.5%, and the heat flux of the gates reaches 6349.2 W/mm2 at 70 mL/min, which is 1172% higher than that of traditional remote cooling. The maximum temperature is only 67.4 °C. Therefore, the embedded microfluidic cooling scheme can markedly suppress the self-heating effect and further explore the electrical potential of GaN-based devices.