Diamond Thermal Conductivity: A New Era in Chip Cooling

Amazing stuff! Diamonds are a chip's best friend!

"When you grow a micrometers-thick layer of diamond inside advanced chips, it spreads out the heat and drops the temperature more than 50°C."

"... But with great power comes great…heat! ...

In some ways, diamond is ideal. It’s one of the most thermally conductive materials on the planet—many times more efficient than copper—yet it’s also electrically insulating. However, integrating it into chips is tricky: Until recently we knew how to grow it only at circuit-slagging temperatures in excess of 1,000 °C.

But my research group at Stanford University has managed what seemed impossible. We can now grow a form of diamond suitable for spreading heat, directly atop semiconductor devices at low enough temperatures that even the most delicate interconnects inside advanced chips will survive. To be clear, this isn’t the kind of diamond you see in jewelry, which is a large single crystal. Our diamonds are a polycrystalline coating no more than a couple of micrometers thick."

Diamond Thermal Conductivity: A New Era in Chip Cooling - IEEE Spectrum "A micrometers-thick integrated layer spreads out the heat"

Gallium nitride high-electron-mobility transistors were an ideal test case for diamond cooling. The devices are 3D and the critical heat-generating part, the two-dimensional electron gas, is close to the surface.

Polycrystalline diamond could help reduce temperatures inside 3D chips. Diamond thermal vias would grow inside micrometers-deep holes so heat can flow from vertically from one chip to a diamond heat spreader in another chip that’s stacked atop it.