GaN-on-Si hotspot thermal management using direct-die-attached microchannel heat sink

GaN-on-Si device posts new challenge to thermal management with its highly concentrated heat flux dissipation from HEMT. In order to characterize GaN-on-Si hotspot and to develop an effective cooling solution, a customized thermal test chip is built with highly doped resistors to produce tiny (150 × 350 μm 2 ) hotspots. Direct-die-attached copper microchannel heat sink is used instead of the conventional slap on heat sink to significantly improve the heat removal rate from the device. By using Infra-red (IR) thermography, the current experimental work demonstrated the cooling capability of microchannel heat sink up to 11.9 kW/cm 2 hotspot heat flux with a maximum hotspot temperature of 175 °C.