Cooling chips with graphene

Graphene-based film on a hot electronic component. Credit: Johan Liu

One of the big issues in electronic chips is heat dissipation. Chips produce heat and the more transistors you have in a chip, the faster they operate the more heat is produced and it needs to be dissipated to maintain the temperature of the chip within acceptable values.

To keep temperature down we have to cool the devices and this cooling is actually accounting for almost 50% of the power consumption!  Self cooling systems are the ideal solution but you need to have efficient ways to dissipate the heat. The best material in terms of heat conductivity that has been available so far is copper.

Now researchers at Chalmers University of Technology have found a way to use graphene as material to dissipate heat.

That graphene has very good heat conductivity was known since its creation but a single layer of graphene "glued" on the chip surface would not work, you need to have many of them to reach a sufficient mass to dissipate heat, actually 20,000 layers of graphene to reach the 20µm thickness. The problem is that it is difficult to make these 20,000 layers of graphene stick on the surface of the silicon. As heat moves through the silicon graphene barrier the graphene detaches itself from the chip. This is because the bonding that keeps the graphene on the silicon is weak (it is a Van der Waals bond for those of you loving chemistry).

At Chalmers they found a way to include in the graphene layer a molecule (3-Aminopropyl triethoxysilane) that makes the bonding strong and develop and industrial process to "glue" the modified graphene on the silicon.

It turns out that the dissipation obtainable with this method reaches 1600W/mK, that is 4 times better than copper.  Cool, in every sense!

Author - Roberto Saracco

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