Thermal-Mechanical Analysis and Optimization of Diamond Heat Sink Packaging for Enhancing GaN HEMT Performance

This study analyzes the thermal-mechanical properties of a power chip package structure using diamond as a heat sink and demonstrates significant performance improvements in GaN HEMTs. Reliable integration between power chips and diamond heat sinks was achieved through optimized nanosilver paste welding, enabling efficient heat dissipation near hot spot. Theoretical simulations showed that diamond heat sinks provided superior heat dissipation and lower thermal stress compared with traditional MoCu heat sinks. Experimental validation with fabricated GaN HEMT chips revealed a 53.4% reduction in the junction-to-case thermal resistance, 45.3% lower maximum chip surface temperature under 27.3 W power dissipation, 9.2% increase in dc output current, and a power cycling lifetime exceeding 330 000 cycles without failure. These findings demonstrate the effectiveness of diamond heat sink packaging in enhancing the thermoelectric performance and reliability of high-power chips.