Co-designed cooling & electronics
Monolithic manifold microchannel cooling (mMMC)
We demonstrated that microfluidics and electronics could be co-designed into the same semiconductor substrate, producing a monolithically-integrated manifold microchannel (mMMC) cooling structure that provides efficiency beyond the state-of-the-art. Our results show that heat fluxes exceeding 1.7 kW/cm² can be cooled down using only 0.57 W/cm² of pumping power. We observed an unprecedented coefficient of performance (>104) for single-phase water-cooling of heat fluxes exceeding 1 kW/cm², corresponding to a 50-fold increase compared to straight microchannels. The proposed cooling technology enables further miniaturization of electronics, potentially extending Moore’s law and greatly reducing energy consumption worldwide.
In-chip cooling for ultra-compact GaN power converters
The dense integration of GaN power ICs generates concentrated heat fluxes exceeding 1 kW/cm², surpassing the limit of current thermal management. We demonstrated the integration of in-chip microfluidic cooling directly on GaN power integrated circuits, with additively manufactured packaging, to achieve ultrahigh power densities. By considering cooling as a third layer of integration alongside power and logic, we realized a 0.44 kW, 48 V–24 V dc–dc converter in a compact 1/32nd brick form factor. Results show a 14-fold reduction in thermal resistance and a 4-fold increase in total output power compared to heat-sink and fan cooling, reaching an outstanding 78 kW/l power density with power conversion efficiency surpassing 95%. This work paves the way for more efficient and highly compact power conversion to support the electrification of our society.
Flow-guided pin fin design for in-chip cooling
Current in-chip cooling designs suffer from thermally parasitic circulation zones that degrade their performance. We introduced a novel flow-guided pin fin design, embedded directly in the chip, that removes circulation zones through streamlined fin extensions, significantly improving thermal performance. This approach achieves a state-of-the-art thermal resistance of 0.04 cm²·K/W at around 1.5 mW/mm² pumping power — 10× lower pumping power compared to conventional approaches, and much more efficient than intricate monolithic designs. Embedded in a commercial GaN HEMT power IC, the design enabled switching frequencies up to 10 MHz (20 W dissipation) with only 5 mW of pumping power, whereas conventional fan cooling was thermally limited to 3 MHz with 560 mW fan power. A full 48 V–12 V converter employing this design delivered 300 W output power (3× higher than a fan-cooled converter) with only 40 °C temperature rise.
