Float-zone material was irradiated with 2MeV electrons at 140K in order to displace substitutional C atoms into interstitial sites. The concentrations of the 2 species were deduced from infra-red localized vibrational mode absorption measurements. Isothermal annealing at 297 to 331K revealed a loss of neutral Ci atoms under first-order kinetics, and the formation of di-C centers. Values for the diffusion coefficient were determined from the known concentration of Cs traps. These data, together with previous electron paramagnetic resonance reorientation data, gave:

D (cm2/s) = 4.4 x 10-1 exp[-0.87(eV)/kT]

A.K.Tipping, R.C.Newman: Semiconductor Science and Technology, 1987, 2[5], 315-7