Growth, optical, and electrical properties of silicon films produced by the metal-induced crystallization process

Amorphous Si (a-Si) and Ni films were deposited by electron beam evaporation on to borosilicate glass (BSG) substrate maintained at ambient temperature. The BSG/a-Si/Ni stack was subjected to post deposition annealing in air at various temperatures from 200 to 500 A degrees C for 1 h. Electron diffraction was employed to characterize the crystallographic phases appearing on the stacks that were depending on initial conditions. Clear evidence of the formation of hexagonal Si and fcc NiSi(2) was shown by TEM. In parallel, an increase of refraction index was observed. Electrical resistivity measurements showed that resistance is of the order of kilo ohms in the as-deposited films, increasing sharply to giga ohms in films annealed at T higher than 300 A degrees C. A large band gap of 2.23 eV which is the combined contribution from a-Si, wurtzite-Si, and Ni silicide phases, is observed.