Managing the heat generated in electronics is a huge problem, especially with smaller package sizes and higher density devices. Usually electronic technologies, designed by electrical engineers, and cooling systems, designed by mechanical engineers, are done independently and separately.
The team at EPFL combined the two with an integrated microfluidic cooling system built into the chip that can directly and efficiently manage the large heat fluxes generated by the transistors.
“Managing the heat produced by these devices is one of the biggest challenges in electronics going forward,” said Prof Elison Matioli at EPFL's Power and Wide-band-gap Electronics Research Laboratory (Powerlab). “It’s becoming increasingly important to minimize the environmental impact, so we need innovative cooling technologies that can efficiently process the large amounts of heat produced in a sustainable and cost-effective way.”
Along with doctoral student Remco van Erp, the team from the Powerlab developed the technique to extract the heat very near the regions that heat up the most in the device.
“We wanted to combine skills in electrical and mechanical engineering in order to create a new kind of device,” said van Erp, lead author on the paper in Nature today.
They etched the microfluidic channels inside the silicon substrate chip to provide cooling for the planar gallium nitride (GaN) transistors on top so that a cooling liquid can flow inside the chip.
“We placed microfluidic channels very close to the transistor’s hot spots, with a straightforward and integrated fabrication process, so that we could extract the heat in exactly the right place and prevent it from spreading throughout the device,” said Matioli. The cooling liquid they used was deionized water, which doesn’t conduct electricity. “We chose this liquid for our experiments, but we’re already testing other, more effective liquids so that we can extract even more heat out of the transistor,” said van Erp.