The thermal stability of the H passivation of Al acceptors in p-type material was investigated. Following passivation by low-energy ion implantation, annealing experiments were performed under an electrical field in a reverse-biased Schottky diode. At temperatures of about 500K, the Al acceptors became reactivated. In order to study the effects of temperature, p-type dopant level and H isotope-type, a mathematical model was developed and was applied to experimental data. The diffusion constant of free H, as well as the dissociation rate, were found to be thermally activated; with energies of 2.1 and 1.2eV.

Quantitative Modelling of Hydrogen Diffusion and Reactivation of H-Passivated Al-Acceptors in SiC. C.Hülsen, N.Achtziger, J.Herold, W.Witthuhn: Materials Science Forum, 2001, 353-356, 331-4