RAMAN-SCATTERING IN AMORPHOUS-SILICON FILMS

Raman spectroscopy is applied to study the microscopic structure of silicon films, chemically vapor deposited at different temperatures T(d). We established, that at T(d) = 450-580-degrees-C the film structure was amorphous. Its ordering increased with T(d)-increasing. At T(d) = 580-620-degrees-C the film structure was mixed: an amorphous matrix with the embedded microcrystals. Minimal crystallites size L = 150 angstrom was estimated both from the TO-phonon broadening and from the intensity ratio of surface-like and bulk crystalline-like modes. At higher temperatures the total number and the average size of the grains increased, its sizes distribution broadened.