ONE-STEP GROWTH OF POLYCRYSTALLINE SILICON THIN-FILMS AT LOW-TEMPERATURE BY ARF EXCIMER LASER-INDUCED PHOTO-CVD

The possibility to grow polycrystalline silicon thin films by laser-induced photochemical vapor deposition in a one-step process is investigated. In this procedure, the pulsed ArF excimer laser is incident perpendicular to the substrate whereas the disilane (Si2H6) gas flow is directed close and parallel to it. In such a perpendicular configuration, the energetic laser beam is thought to simultaneously dissociate the Si2H6 molecules and to allow the growth of the silicon film. Both morphological and microstructural properties of so-grown silicon films are investigated. Raman spectroscopy and transmission electron microscopy experiments show that good quality polycrystalline silicon layers are easily obtained using moderate laser fluence (50-100 mJ/cm2) with the substrate maintained at room temperature. Profilometry measurements and scanning electron microscopy observations reveal that the surface roughness increases with the laser energy density.