New chip coated with man-made diamonds promises smaller, more powerful radars

Diamonds aren’t just forever. They’re also a great conductor of heat.

A new type of semiconductor prototyped by DARPA and Raytheon promises to run much cooler than typical chips, a breakthrough that could lead to much better radars for warplanes, drones, and air defense systems. 

Raytheon is getting $15 million to further develop these extra-cool gallium nitride, or GaN, semiconductors under DARPA’s Technologies for Heat Removal in Electronics at the Device Scale, or THREADS, program. 

“The way we're trying to achieve that is by integrating some of the world's best thermal conductors right next to the hotspot in the device,” Matt Tyhach, Raytheon’s mission area director for next-generation sensors and microelectronics, told Defense One ahead of the announcement. 

The conducting material? Diamond crystals grown onto chips with help from Diamond Foundry and Stanford. New breakthroughs in nanotechnology and lab-grown diamonds make it possible. 

Diamond is one of the world’s best thermal conductors. In fact, if you took a diamond crystal wafer between your fingertips and touched the other end to an ice cube, the wafer would transfer the heat from your fingertips and melt the cube. That same property could lead to gallium nitride chips that require less cooling. 

Gallium nitride is already a common component in radar systems, helping to maximize the power of the emissions that reflect off incoming threats. But like all electronics, heat can be a limiting factor. Enter diamond crystals. 

“In terms of comparing thermal performance, today's silicon carbine substrates have a conductivity of about 300 [Watts per meter-Kelvin]. The diamond is 2,000,” Tyhach said.

What could you do with much cooler gallium nitride semiconductors? Tyhach said DARPA is working on the applications. But in the same way gallium nitride enabled a new generation of radars that were smaller and more powerful than their predecessors, so could new semiconductor architectures enable drones or fighter jets with much more powerful radar and sensing ability, he said. That could leave more room for additional autonomy and allow the drone or jet to much more accurately perceive the world around them, letting them find targets or evade threats more easily. 

The work will take place in Raytheon’s gallium nitride foundry in Andover, Massachusetts. 

“The same foundry that makes that GaN wafers today will be used to make the devices for the THREADS program as well. So the fact that we're doing research on the same tools of production really helps accelerate the period from development to transition,” Tyhach said.