Low-temperature infra-red spectroscopic experiments were performed on the annihilation of 6 species of thermal double donor under various conditions in both C-poor and C-rich crystals. It was found that 2 types of thermal double donor annihilation occurred in 2 different time regions. The first annihilation typically occurred within 17h at 500C, and was attributed to dissociation of the O clusters which were responsible for thermal double donors. Thermal double donor annihilation was analyzed on the basis of a model which involved the successive dissociation of O clusters. This yielded an activation energy of about 4eV and a pre-exponential factor of the order of 1022/s; regardless of the thermal double donor species and C density. The second annihilation typically occurred after 17hr at 500C, and was attributed to the neutralization of thermal double donors. The neutralization behavior depended strongly upon the amount of C in the crystals. The C-rich crystals exhibited the usual thermal activation behavior; with an activation energy of 1.7eV and a pre-exponential factor of about 106/s; regardless of the thermal double donors species. On the other hand, the C-poor crystals exhibited no distinct temperature dependence upon the neutralization rate; thus indicating an athermal process. The results strongly suggested 2 different mechanisms for thermal double donor neutralization; one of which was related to C while the other was independent of C.

Annihilation of Thermal Double Donors in Silicon Y.Kamiura, Y.Takeuchi, Y.Yamashita: Journal of Applied Physics, 2000, 87[4], 1681-9