Structural characterization of microcrystalline-amorphous hydrogenated silicon samples prepared by PECVD method

Microcrystalline-amorphous doped hydrogenated silicon (μc n⁺ a-Si:H) samples were prepared by using plasma enhanced chemical vapor deposition (PECVD) method. The samples were deposited on coming substrates at 270°C and then were annealed at 250°C during several hours. Raman scattering spectroscopy was employed to study the amorphous-microcrystalline (μc/a) phase transition and the subsequent microcrystallization process as a function of the annealing time. It was found that the conductivity of the material is closely related to the normalized Raman intensity of the LO mode. In this work, such relation is explained in terms of the impurities activation and by the hydrogen effusion, which takes place during the annealing process. Samples morphology was characterized by atomic force microscopy (AFM). Crystallized silicon islands were observed with an average diameter depending on the annealing time.