Raytheon Company of Waltham, MA, USA says that it has achieved another milestone for next-generation gallium nitride (GaN) radio-frequency (RF) semiconductor technology. Through the US Defense Advanced Research Projects Agency (DARPA) Near Junction Thermal Transport (NJTT) effort under the Thermal Management Technologies program, Raytheon’s team is replacing GaN’s current substrate silicon carbide (SiC) with diamond, a material with 3-5x higher thermal conductivity, to create GaN-on-diamond devices.

Raytheon has demonstrated that GaN-on-diamond technology enables a 3x increase in transistor power density over GaN-on-SiC, overcoming a major barrier to unlocking the potential of GaN devices, it is reckoned. Data was obtained on a 10 x125μm GaN-on-diamond high-electron-mobility transistor (HEMT), a device representing a unit cell for constructing power amplifier monolithic microwave integrated circuits

(MMICs), which are the foundation of solid-state RF transmitters and active electronically scanned arrays (AESAs). Raytheon says that this lattest result builds on prior successes, including its industry-first demonstrations of GaN-on-diamond transistors in 2009 and of GaN-on-diamond MMICs in 2011.

“We are now inserting GaN into DoD systems while remaining focused on continuing to increase performance of this revolutionary semiconductor to provide our warfighters with the most advanced sensing, communications and electronic warfare capabilities in the world,” says Joe Biondi, VP of Advanced Technology for Raytheon’s Integrated Defense Systems (IDS) business in Tewksbury, MA.

GaN-on-diamond offers performance improvement by reducing thermal resistance within the device and enabling GaN to be used at higher power densities, which can dramatically reduce the cost, size, weight and power of defense systems, says Raytheon. GaN is a core competency within Raytheon and an integral technology behind some of the its major programs, including the US Navy’s Air and Missile Defense Radar program (AMDR) and the Next Generation Jammer (NGJ) program. GaN’s unique qualities allow radar, electronic warfare and communications systems to be smaller, more affordable and highly efficient, says Raytheon.

Raytheon also recently announced that, under the DARPA Microsystems Technology Office (MTO) Wide Bandgap Semiconductor (WBGS) program, it has systematically matured GaN from basic material to transistors, MMICs, transmit/receive (T/R) modules and finally transmit/receive integrated multi-channel modules (TRIMMs).