Nanocrystalline diamond thin film integration in aluminum gallium nitride/gallium nitride high electron mobility transistors and 4H-silicon carbide heterojunction diodes

The extremely high thermal conductivity and mechanical hardness of diamond would make it the natural choice for device substrates when large area wafer production becomes possible. Until this milestone is achieved, people could utilize nanocrystalline diamond (NCD) thin films grown by chemical vapor deposition (CVD). A topside thermal contact could be pivotal for providing stable device characteristics in the high power, high temperature, and high switching frequency device operating regime that next-generation power converter circuits will mandate. This work explores thermal and electrical benefits offered by NCD films to wide bandgap semiconductor devices. Reduction of self-heating effects by integrating NCD thin films near the device channel of AlGaN/GaN high electron mobility transistors (HEMTs) is presented. The NCD layers provide a high thermal conductivity path for the reduction of hot electron dispersion, a phenomenon caused by self-heating and detrimental to the continuous operation of GaN devices in power switching circuits.