Elimination of Leakage in GaN-on-Diamond

The use of chemical vapor deposition diamond as a substrate for gallium nitride (GaN) to form GaN- on-diamond has the potential to allow for higher linear power densities in GaN high electron mobility transistors (HEMTs). The increase in GaN HEMT power density on diamond has been limited to date by the electrical leakage in GaN-on-diamond substrates. In this paper we show that to eliminate buffer leakage in silicon based GaN-on- diamond, you have to completely remove the transition layers used to grow high quality GaN on the original host silicon. By completely removing the transition layers in GaN-on-diamond, we demonstrated buffer leakage comparable to the leakage in GaN on silicon carbide.