Efficiently removing excess heat becomes increasingly difficult as electronic devices are miniaturized and produce higher heat fluxes, placing greater demands on cooling systems. Microfluidic cooling systems, in which a coolant is used to transfer heat away, have been developed to manage heat in electronic chips. However, conventional approaches rely on external heat sinks, which make the setup bulky, or embedded microchannel heat sinks that are added onto the chip through a complex fabrication process. Elison Matioli and colleagues at the École Polytechnique Fédérale de Lausanne have now developed a gallium-nitride-on-silicon chip that monolithically integrates a microfluidic cooling system.
In a combined fabrication approach, the researchers create multiple microchannels (to act as heat sinks) in the silicon layer and create electronic devices (an a.c. to d.c. power converter) in the gallium nitride layer. To further lower the temperature of the chip, a coolant can flow through the microchannels, which sit directly below the electronic components. When water coolant was used, the structure could remove 1.7 KW cm–2 of heat using only 0.57 W cm–2 of pumping power, outperforming other state-of-the-art cooling systems. Furthermore, compared to an air-cooled device, the liquid-cooled converter had a higher power output due to reduced self-heating effects.
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Varnava, C. Chips cool off with integrated microfluidics. Nat Electron 3, 583 (2020). https://doi.org/10.1038/s41928-020-00494-5