A Germanium-Tin Alloy Could Let Future Chips Harvest Their Own Heat Energy
With exajoules of energy wasted every year, harnessing heat as an energy source could make future computers a lot more eco-friendly.
Researchers from the Forschungszentrum Jülich, the Leibniz Institute for High Performance Microelectronics (IHP), the University of Pisa, the University of Bologna, and the University of Leeds have come up with a new material that, they say, can be integrated into existing CMOS technology to turn processors' waste heat into electricity.
"In the paper we made a very important step. We have evaluated one of the most critical parameters for a thermoelectric material, the thermal conductivity, using a suite of different experimental techniques on epitaxial samples with different alloy compositions and thicknesses," claims IHP project lead Giovanni Capellini of the team's work. "Our joint research can have a sizeable impact in the field of 'Green IT' infrastructures."
The researchers' paper details a way to add thermoelectric energy harvesting to future semiconductor chips through the addition of a germanium-tin alloy. "Adding tin to germanium significantly reduces the material's thermal conductivity while maintaining its electrical properties, an ideal combination for thermoelectric applications," explains Forschungszentrum Jülich's Dan Buca.
This alloy can be integrated into the existing process for making CMOS chips, the researchers say, and help to turn some of the waste heat — estimated at 1.2 exajoules per year in Europe alone, and set to rise as the industry attempts to deliver compute to meet the demands of the burgeoning artificial intelligence boom — into usable energy.
"The results highlight the high potential of single-crystal GeSn [Germanium-Tin] alloys to achieve similar energy harvest capability as already present in SiGe [Silicon-Germanium] alloys but in the 20°C-100°C [68°F-212°F] temperature range where Si-compatible semiconductors are not available," the team concludes. "This opens the possibility of monolithically integrated thermoelectric on the CMOS platform."
The team's work has been published in the journal ACS Applied Energy Materials under open-access terms.
Main article image courtesy of ACS Applied Energy Materials.