The diffusion and out-diffusion properties of H were investigated in homo-epitaxial layers of chemical vapour deposited B-doped diamond which had been exposed to a D microwave plasma. Diffusion experiments showed that the onset of (B,H) pair dissociation occurred at 550C. The activation energy for H diffusion was equal to 1.4eV. The H out-diffused at 880C, and the diamond surface barrier limited the out-diffusion process. In radio-frequency plasma-exposed diamond epilayers, the H out-diffusion spectra contained a peak at 720C which was related to the sub-surface H accumulation layer. Another peak at 840C was attributed to H which was adsorbed at the surface.

Diffusion and Thermal Stability of Hydrogen in Homoepitaxial CVD Diamond Films. D.Ballutaud, F.Jornard, J.Le Duigou, B.Theys, J.Chevallier: Diamond and Related Materials, 2000, 9[3-6], 1171-4