It was recalled that hydrogen was theoretically predicted to be present in diamond in one of the three charge states, H+, H0 and H-. Moreover it could form complexes with impurities, native defects or with other hydrogen atoms. This work comprised two parts: (a) a review of previous results of studies investigating different aspects of the diffusion of hydrogen (deuterium) in various kinds of diamond. The diamonds studied were: undoped type IIa diamonds, undoped CVD diamond layers containing growth defects only, p-type B-doped homo-epitaxially CVD grown diamond layers or B ion-implanted type IIa diamonds and n-type P doped homo-epitaxially CVD grown diamond or N-doped type Ib natural diamonds. Hydrogen was introduced into diamond by exposing the diamond surface to hydrogen plasma or by using hydrogen ion implantation. Considered were the influence of the interaction between H and the dopants and defects upon hydrogen diffusion, the kinetics of (B, H), (P, H) and (N, H) pair formation and dissociation and modification of the optical and electrical properties resulting from hydrogen incorporation and annealing. It was found that, under certain conditions, H diffused into the B containing layer and passivated B acceptors. In contrast, no H diffusion could be observed in n-type diamonds, up to 1000C. Previous results regarding other aspects related to the diffusion of H in diamond were presented. These included results on the influence of ion implantation-related defects on the diffusion of deuterium. For this study, type-IIa samples implanted with B or non-dopant ions were used. Also covered was the determination of the charge state of H or H/defect complexes as a function of diamond type. For this, annealing under bias was applied to deuterated diamond layers. It was shown that the presence of implantation defects retarded deuterium diffusion in B-implantation doped diamond, demonstrating that D interacted strongly with defects; thus inhibiting diffusion. The newly-formed complexes deteriorated the electrical properties of the diamonds and were very stable up to high temperatures. It was confirmed that, as expected, in highly B-doped CVD diamond layers, H diffused as a positive ion. In lightly B-doped homo-epitaxial layers, however, D was incorporated into complexes which seemed to be negatively charged.

Diffusion of Hydrogen in Undoped, p-Type and n-Type Doped Diamonds. Saguy, C., Cytermann, C., Fizgeer, B., Richter, V., Avigal, Y., Moriya, N., Kalish, R., Mathieu, B., Deneuville, A.: Diamond and Related Materials, 2003, 12[3-7], 623-31