On the physical models of annealing of radiation induced defects in amorphous Sio 2

Abstract

Radiation induced defects in amorphous SiO 2 such as the oxygen-vacancy center and the non-bridging oxygen-hole center are assumed to anneal by the trapping of diffusing molecular species such as O 2, H 2O and H 2. In an amorphous network such diffusion is not expected to proceed with a unique activation energy given the randomness of the structure. Diffusion based models assuming a distribution of activation energies have been shown to explain observed isochronal and isothermal annealing curves. It is demonstrated here that the “stretched exponential” form exp- t τ β with 0 < β < 1 gives an excellent description of defect annealing in amorphous SiO 2 Fitting indicates that the annealing of oxygen-vacancy centers in “wet” oxide proceeds with an activation energy of 0.96 eV which may be attributed to H 2O diffusion.