On Extracting the Maximum Power Density at High Frequencies from Gallium Nitride and Related Materials

The demand for higher power density in electronic applications has made Gallium Nitride HEMT technology a front-runner in both power and RF applications due to its exceptional material properties. However, to fully unleash GaN's potential, thermal management is crucial to address the issue of severe Joule heating causing performance degradation and premature failure. A potential solution lies in integrating diamond, known for its excellent thermal properties, with GaN HEMTs. Although diamond growth on GaN has been challenging, a recent breakthrough in our group has demonstrated successful diamond-on-GaN integration using a low-temperature growth process
$(\sim 400^{\circ}\mathrm{C})$
. The integrated diamond films showed high thermal conductivity (300 W/m/K) and phase purity (97%), resulting in significantly reduced peak temperature in GaN HEMT channel by
$> 100^{\circ}\mathrm{C}$
during operation at 20 W/ mm. This advancement opens up new possibilities for improving the efficiency and performance of GaN-based electronics.