Diamond gets heat from GaN RF
TriQuint has received a $2.7m contract from US military funding agency DARPA to triple the power handling of GaN RF circuits using, amongst other things, diamond heat spreaders and the assistance of the University of Bristol.
The Near Junction Thermal Transport (NJTT) effort will build on TriQuint’s GaN-on-SiC technology.
“Many defence semiconductor power amplifiers and other high-power electronic and photonic components are thermally limited by the high thermal resistance of the region within 100µm of the electronic junction, also known as the near junction region,” said DARPA. “The goal of the NJTT effort of is to achieve a 3x or greater improvement in power handling from GaN power amplifiers through improved thermal management of the near junction region.”
The firm said the near-junction region plus the device substrate can be responsible for more than 50% of operational temperature increases.
“NJTT will set the stage for substantial MMIC performance enhancements including reduced size, weight and power consumption while increasing reliability and output power,” said TriQuint v-p for defence products James Klein.
SiC is already a better thermal conductor that sapphire – the other popular wafer for GaN epitaxy.
TriQuint intends to combine GaN-on-SiC with diamond substrates and “new thermal handling processes” to get heat out, it said.
Partners in the programme include: the University of Bristol, Group4 Labs and Lockheed Martin.
“The University of Bristol is recognised for its leadership in thermal testing, modelling and micro Raman thermography,” said TriQuint. “Group4 Labs is a pioneer in the use of diamond substrates and has worked with TriQuint to demonstrate diamond’s potential as a substrate material. Lockheed Martin will evaluate the results of the program for its projected impact on future defence systems.”