A feasibility study was made of the solid-phase diffusion of C into GaN by using a SiNx/CNx/GaN structure prepared by electron-cyclotron resonance-assisted chemical vapor deposition. An X-ray photo-electron spectroscopy study of the CNx layer deposited on GaN showed that its energy positions and spectrum features were very close to those of a C–N bond, and the N composition was estimated to be 24%, indicating a highly C-rich layer. No degradation in the chemical properties of the GaN surface was found after the diffusion process at 1000C. A secondary ion mass spectrometry result clearly showed a diffusion of C into GaN. An increase in resistivity for the C-diffused GaN layer was also observed.

Solid-Phase Diffusion of Carbon into GaN Using SiNx/CNx/GaN Structure. T.Kimura, S.Ootomo, T.Nomura, S.Yoshida, T.Hashizume: Japanese Journal of Applied Physics, 2007, 46[10], L224-6