Near-junction microfluidic thermal management of RF power amplifiers

While gallium nitride (GaN) is attracting broad attention as the wide bandgap material of choice for both industrial and defense applications, thermal impediments present a significant barrier to full exploitation of its inherently high electron sheet charge density and electrical breakdown voltage. For the last four years, the Defense Advanced Research Projects Agency (DARPA) has pursued research focused on reduction of near-junction thermal resistance through use of diamond substrates and convective and evaporative microfluidics. The options, challenges, and techniques associated with the development of this embedded thermal management technology are described, with emphasis on the accomplishments and status of efforts related to GaN power amplifiers.