DARPA, Raytheon developing diamond-based GaN microchips

A new, flexible silicon-on-polymer chip developed by the US Air Force Research Laboratory (AFRL) and American Semiconductor has a memory capability 7,000 times higher than the current slate of flexible, integrated circuits on the market. (US Air Force)

The Defense Advanced Research Projects Agency (DARPA) is teaming with Raytheon to develop new diamond-based substrates for gallium nitride (GaN) semiconductors in a bid to push high-powered radar and radio frequency (RF) communication applications down to the tactical level.

A wide-bandgap semiconductor known for its extreme durability and stable transmission speeds, GaN-enabled microelectronics (ME) systems have routinely performed better than comparable silicon-based ME systems. “It is really the heartbeat of our systems, in terms of RF performance … whether [the] systems are radars, or [electronic warfare] or missiles”, according to Matt Tyhach, Raytheon's mission area director for next-generation sensors and microelectronics.

To that end, officials from the Department of Defense's (DoD's) Office of the Under Secretary of Defense for Research and Engineering (OUSD R&E) kicked off its Technology for Nitrogen-Polar Gallium Nitride: Epiwafers & Substrates (ECLIPSE) programme in August 2022. The N-polar GaN ME material and related substrates being sought by the US armed forces will be a “key technological enabler for millimeter wave (mmW) applications”, according to Pentagon officials.

While N-polar GaN ME materials have proven critical in mmW applications, the high operating temperatures of GaN semiconductors have prevented their use in lower frequency applications at S-band or X-band frequencies.

“GaN itself has always been thermally limited,” he told Janes