HOLE CAPTURE IN BORON-DOPED DIAMOND

A carrier capture model based on the work of Lax [Phys. Rev. 119, 1502 (1960)] and Gibb et al. [Philos. Mag. 36, 1021 (1977)] is applied to diamond. This model accounts for the lower activation energy for boron in diamond measured using deep level transient spectroscopy (DLTS) techniques. The model assumes that when a carrier in the valence band is captured by an impurity, it occupies the highest energy acceptor excited state and then is quickly funneled to the lowest excited acceptor level. At the lowest energy excited acceptor level the trapped hole either thermalizes back to the valence band or reaches the ground state of the impurity via a ''slow'' multiphonon decay. Using this kinetic picture, previously reported DLTS results are shown to be consistent with the energy parameters for the boron acceptor level. These results will be of interest to researchers simulating the device properties of diamond and are an indication of the influence of the acceptor spectrum on the electrical properties of boron-doped diamond.