Aluminum induced rapid crystallization of amorphous silicon films in an electric field at low temperature

The a-Si films were deposited on Al-coated 7059 glass substrates by plasma enhanced chemical vapor deposition, and the formed a-Si/AI/glass structure samples were thermally annealed at a temperature range of 400-550 °C for duration time of 5-60 min in absence and presence of an electric field, respectively. The annealed samples were characterized by X-ray diffraction spectra and Raman scattering spectroscopy. The a-Si film of 1.2 μm, annealed at 400 °C for 60 minutes, completely transforms into poly-Si film in the presence of an electric field of 30 V/cm, while only 15% volume fraction of a-Si film crystallize into poly-Si at the same annealing conditions but in absence of electric field. When the intensity of the electric field increases to 120 V/cm, all of a-Si film transform completely into poly-Si at 450 for only 30 min. The enhancing effect of the biased electric field on the Al induced solid phase crystallization of a-Si is apparent, and the mechanism of this effect is discussed briefly.