The incorporation of H into n-type samples was investigated via its non-intentional introduction during growth and during post-growth diffusion experiments. In the first case, (111) n-type diamond homo-epitaxial films doped with P were grown by microwave plasma chemical vapor deposition from a CH4+D2 mixture. The P concentrations ranged from 1.3 x 1018 to 3 x 1019/cm3. The concentration of D incorporated was usually 100 times below the P concentration; thus indicating an absence of donor passivation by H in the films. These D concentrations were well below the H concentration of 1021/cm3 reported in undoped (111) homo-epitaxial diamond films. Exposure of P-doped and N-doped diamonds to D plasma revealed an absence of D diffusion; even at 1000C. The high migration energy of H-, combined with the strong H-donor interactions and self-trapping of H, were suggested to be possible reasons for the absence of significant H diffusion. In natural type-Ia diamonds, a H-related vibrational band was frequently observed at 3107/cm. On the basis of the similarity of some properties of this band and of the bands related to well-known (H, impurity) complexes in conventional semiconductors, it was proposed that (N,H) complexes were responsible for this absorption band.

Hydrogen in n-Type Diamond. J.Chevallier, F.Jomard, Z.Teukam, S.Koizumi, H.Kanda, Y.Sato, A.Deneuville, M.Bernard: Diamond and Related Materials, 2002, 11[8], 1566-71