In-Chip Microfluidic Cooling Integrated on GaN Power IC Reaching High Power Density of 78 kW/l

The lateral structure of gallium nitride (GaN) semiconductors enables monolithic integration of logic and power devices, which offers promise to miniaturize bulky converters into a compact package. However, the concentrated heat that arises from this dense integration can locally exceed 1 kW/cm ² , which surpasses the limit of current thermal management technologies. In this article, we demonstrate the potential of integrating in-chip microfluidic cooling directly on GaN power integrated circuits (ICs), together with additively manufactured packaging, to provide efficient thermal management, and achieve ultrahigh-power densities. A prototype power module and a 0.44 kW 48 V–24 V dc--dc converter were realized in a compact 32nd brick form factor to demonstrate its potential. Our results show a 14-fold reduction in thermal resistance and a four-fold increase in the total output power compared to heat-sink and fan cooling. An outstanding 78 kW/l was achieved, together with an increase in power conversion efficiency, surpassing 95%. By removing thermal limitations from power IC design, and enabling highly integrated topologies combined in a single liquid-cooled chip, this work paves the way for more efficient and highly compact power conversion in the future to support the electrification of our society.