Microchannel Cooling for Performance Enhancement of GaN-on-Si HEMT With a Low R j-a of 13.5 K/W

Gallium nitride (GaN) is a high-performance wide bandgap semiconductor material with unique physical and chemical properties such as higher breakdown electric field, higher electron density, superior electron mobility and saturation velocity. These properties endow GaN with unparalleled advantages in high-frequency and high-power applications. However, a primary challenge faced by the industrialized GaN HEMT is thermal management, particularly in handling higher power densities, which leads to a serious degradation in electrical performance and long-term reliability. In this study, electrothermal analysis for GaN HEMT is conducted based on two thermal resistance models for natural air cooling and microchannel cooling, proving a minimum 40% reduction in Rj-a using microchannel cooling and an optimal coolant flow rate to guide the actual experiment. Furthermore, the experimental result shows that microchannel cooling technology significantly enhances the thermal convection capacity, resulting in a 35.2% increase in the saturation current. Moreover, the Rj-a can be reduced to 13.5 K/W with 65% improvement at a cooling flow rate of 460 mL/min, and the surface heat flux density reaches 2200 W/cm2, which is 106% higher than that of natural air cooling.