Near-Junction Thermal Management of GaN-on-SiC MMIC Power Amplifier Through Substrate Embedded Microchannel

Self-heating inhibits the electrical characteristics improvement of GaN devices. The local hotspots generated in the gate region significantly affect the output performance of GaN devices. This study proposes a near-junction cooling technique for the thermal regulation of a GaN-on-SiC monolithic microwave integrated circuit power amplifier (MMIC PA). An embedded microchannel structure is integrated into the GaN-on-SiC high-electron-mobility transistor (HEMT) substrate. The dc characteristic curve of the actual HEMT reveals that the designed embedded cooling microchannel induces a 22.32% increase in saturation current and an 11.74% enhancement in device transfer characteristics and effectively mitigates the impact of device heat on dc output properties. The microchannel design of a single HEMT model is applied to design the characteristic parameters of the MMIC PA. Embedded cooling can effectively eliminate the thermal coupling between two HEMTs on MMIC PA at a certain distance. Consequently, the implementation of embedded cooling in the thermal management of high-power MMIC PAs markedly augments the output performance. This is an effective and innovative method for the thermal management of high-power amplifiers.