Structural changes in thin amorphous silicon film during electron irradiation

It is shown by methods of Raman spectroscopy that irradiation of amorphous silicon film 50 nm thick by focused electrons with energies of 5-10 keV results in its crystallization at temperatures much less, than the temperatures of melting and annealing of silicon. Analyses have shown that crystallization is caused by the formation of negative charge area on a film surface, by the action of secondary electrons on chemical bonds and mutual location of silicon atoms, and also by the ionic field emission of silicon ions and their field migration to the irradiated zone from surrounding regions. These processes result in the change of equilibrium location of silicon atoms, typical for amorphous phase. The increase of electron energy leads to the increase of crystallization process efficiency.