Fermi-Dirac statistics and the nature of the compensating donors in boron-doped diamond layers

Fermi-Dirac statistics have been applied to semiconducting diamond layers doped with boron by means of ion implantation. Suitable limiting equations could be derived to describe the resistance-temperature behavior which relates to acceptor activation and also to hole creation in the valence band by means of compensating-donor neutralization. When applying these equations to the experimental data, it is found that the donor centers have a very large degeneracy weighting factor $g_D$ and that this parameter depends on the annealing cycle used after ion implantation. This result can be explained by assuming that the donors consist of small aggregates of vacancies which constitute vacancy-lattice ‘‘crystallites.’’ In this paper, we shall call these particular vacancy aggregates, which have a stable electronic structure, vacloids. The presence of vacloids may also be invoked to explain some of the optical properties previously observed in diamonds.