Thin films of nanocrystalline silicon (nc-Si) are considered among the most attractive materials for the third- and next generations of solar cells and other optoelectronic devices. This chapter shows the mechanism of Tin-induced crystallization of amorphous silicon manufactured by physical vapor deposition method and possibility of crystallization control during laser annealing. A controlled crystallization of amorphous silicon films from the amorphous state was studied intensively during the past decades. Recently, those studies gained an additional momentum due to advances with metal-assisted transformation of amorphous Si (a-Si) into a crystalline state Silicon doping withtin (Sn) proved to be an effective and convenient method of influencing various properties of Si. The amorphous versus crystalline phase composition of the films and structures was analyzed using room temperature Raman spectroscopy (RS) activated with laser at the wavelength of 514.5nm and 633 nm. The impurity distribution profiles across the films were characterized by Auger electron spectroscopy of reactive ion etched (RIE) films.