A kinetic many-body electron-related model was proposed for the crystallization of F-doped amorphous hydrogenated material in the presence or absence of metal contacts. The model expressed the formation parameters of crystalline nuclei in terms of atomic and electronic material characteristics. The model was based upon the kinetic electron-related theory of thermally activated rate processes in solids. The model considered ps atomic and electronic phenomena which occurred in the nm-vicinity of strongly fluctuating Si atoms which executed diffusion-like jumps over energy barriers and into more ordered positions which were associated with the formation of crystalline nuclei. The effect of random ps fluctuational heating (cooling), in the nm-vicinity of hopping atoms, upon the nucleation (crystallization) rate was considered. From a kinetic consideration of crystallization processes, Arrhenius-like equations were found (for the nucleation time) which linked it to Si self-diffusion in the metal/semiconductor interface. These equations were in agreement with experimental data. The Arrhenius activation energy and the pre-exponential factor for the nucleation process were also calculated. They were expressed in terms of local parameters which characterized ps atomic and electronic processes that occurred in the nm-neighborhood of the hopping Si atoms. Abnormally large variations in the pre-factor (some 11 orders of magnitude) and

activation energy (factor of 7.5) which were caused by metal contacts were considered. An explanation was suggested for the linear relationship between the logarithm of the pre-exponential factor and the activation energy, as observed experimentally in the case of the crystallization of amorphous hydrogenated or fluorinated material. The coefficients in this compensation-effect equation, and other kinetic parameters, were calculated and were expressed in terms of material characteristics. They were found to be in good agreement with experimental data. An explanation was also suggested for large observed differences in the rate of nucleation in amorphous hydrogenated or fluorinated material. The Si self-diffusion coefficients were calculated from the nucleation parameters of the plain materials as well as of samples which were in contact with Al or Pd.

J.L.Khait, R.Weil: Journal of Applied Physics, 1995, 78[11], 6504-13