DARPA has awarded Raytheon a $15m four-year contract to increase the power density of GaN power devices in military radar.

RTX-DARPA-THREADS Raytheon high-power-density GaN
“The improved transistors will have 16 times higher output power than traditional Gallium Nitride with no increase in operating temperature,” according to the company.

“Thermal management is no longer a limiting factor,” added Raytheon president Colin Whelan.

Key to this is the use of diamond to extract heat, with its thermal conductivity above 2,000W/m/K, compared with ~400 for copper.

DiamondFoundry GaV-on-diamondGaN on single-crystal diamond from Diamond Foundry

As part of a DARPA programme known as Threads (Technologies for heat removal in electronics at the device scale), Raytheon in Massachusetts will be working with the US Naval Research Laboratory, Stanford University and Diamond Foundry to grow diamond – the latter already bonds GaN to its diamond substrates.

Cornell University, Michigan State University, the University of Maryland and Penn State University  are also involved.