Researchers at Osaka Metropolitan University have successfully fabricated gallium nitride (GaN) high electron mobility transistors using diamond as a substrate.

GaN transistors are high-power, high-frequency semiconductor devices used in mobile data and satellite communication systems.

In a paper published in the journal Small, the scientists explain that with the increasing miniaturization of semiconductor devices, problems arise such as increases in power density and heat generation that can affect the performance, reliability, and lifetime of these devices. Therefore, effective thermal management is crucial. 

Diamond, which has the highest thermal conductivity of all natural materials, is an ideal substrate material but has not yet been put to practical use due to the difficulties of bonding diamond to GaN elements.

Their novel technology, however, has proven to have more than twice the heat dissipation performance of transistors of the same shape fabricated on a silicon carbide (SiC) substrate. 

To maximize the high thermal conductivity of diamonds, the team integrated a 3C-SiC layer, a cubic polytype of silicon carbide, between GaN and diamond. This technique significantly reduces the thermal resistance of the interface and improves heat dissipation.

“This new technology has the potential to significantly reduce CO2 emissions and potentially revolutionize the development of power and radio frequency electronics with improved thermal management capabilities,” lead researcher Jianbo Liang said in a media statement.