The infra-red absorption coefficient of the 0.009mm band was measured by using Fourier transform infra-red spectroscopy at temperatures ranging from 77 to 775K. It was found that the center of the 0.009mm band shifted to longer wavelengths with increasing temperature. The interstitial O concentration was almost constant at temperatures below 600K, but decreased rapidly at temperatures above 600K. The results confirmed that there were 2 types of O configuration: a bonded Si2O configuration with a binding energy of 0.8 to 1.0eV at 77 to 600K, and a Si2O configuration which coexisted with a quasi-free interstitial O state at temperatures above 600K. The lattice potential barrier, which impeded the migration of quasi-free interstitial O atoms in the lattice, was estimated to be between 1.5 and 1.6eV. The anomalous diffusivity of O could be quite well explained in terms of these configurations.

C.S.Chen, F.Q.Zeng, Y.X.Huang, H.J.Ye, C.M.Hu, D.K.Schroder: Applied Physics A, 1992, 55[4], 317-23