Film forming processing epitaxy

A high preferential (100) orientation of the poly-Si surface is favorable for subsequent epitaxial growth at low temperatures [41-43]. Due to the preferential (100) orientation, the utilization of the poly-Si films formed by the ALILE process as a template (seed layer) for subsequent epitaxial thickening at low temperatures is quite attractive [44]. 

When a clean metallic surface is exposed to ordinary ambient air, it acquires a contaminating film. Every common metal, with the exception of gold, reacts with the oxygen of the air to form an epitaxial film of oxide. In addition, there is a physically adsorbed film, comprised of oxygen, carbon dioxide, water vapor and other atmospheric constituents, that lies on top of the oxide layer. Consequently the process of "cleaning" surfaces for friction studies by abrasion, polishing, water-washing... 

The study of the thin film deposition process shows that the film structure is strongly dependent on the crystal and energetic properties of the surfaces in contact. As a rule, the epitaxial contact between two phases is the most energetically favourable, but because of the high deposition rate of the thin films an amorphous structure is formed instead of an epitaxial layer. With increase of the film thickness or at higher temperatures, the amorphous phase is converted into a crystalline film. 

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