Thermal structure analysis of the TP-HDPS in High-Power Chip: Their application to GaN HEMTs

This paper proposes a two-phase heat-dissipation packaging structure (TP-HDPS) for near-junction thermal management of GaN HEMT. It consists of a metal shell, a ceramic substrate, and a GaN HEMT die packaged with a heat sink and liquid coolant. In this study, a computational fluid dynamics (CFD) numerical simulation was conducted to study the heat-dissipation performance of TP-HDPS. Compared with the traditional package structure, TP-HDPS can effectively reduce the junction-to-case thermal resistance of GaN HEMTs. Based on the optimized TP-HDPS using the CFD model, the thermal resistance from the junction to the case was reduced by 84.06%. In addition, a TP-HDPS with GaN-on-Si HEMT die was prepared and measured, which can achieve an 22.71% decrease in the junction-to-case thermal resistance at the power density of 209.5W/cm² and an 8.77% improvement in electrical properties compared with that of its counterpart without phase change. Also, it can also be demonstrated that the minimum thermal resistance occurs at the power density of 500 W/cm² with a 32.87% reduction for TP-HDPS with CuMo heatsink and 40.49% reduction for TP-HDPS with diamond heatsink compared with their counterpart without HFE7100.