STRUCTURE OF POLYCRYSTALLINE SILICON THIN-FILM FABRICATED FROM FLUORINATED PRECURSORS BY LAYER-BY-LAYER TECHNIQUE

We observed the structure of polycrystalline silicon (poly-Si) fabricated from fluorinated precursors, SiFnHm (n+m less than or equal to 3), by repeated deposition of very thin layers, 10 nm thick, and atomic hydrogen treatment (H-treatment). The surface views and the cross-sectional views of poly-Si were observed using a field-emission scanning electron microscope (FE-SEM) and transmittance electron microscope (TEM), respectively. Poly-Si was made up of columnar crystalline grains of which diameters were 200 nm or more. These columnar crystalline grains grew perpendicularly on the amorphous layer grown directly on the glass substrate. Crystalline nuclei were formed within the amorphous layer and grew into crystalline grains with the aid of H-treatment. The thickness of this incubation layer was dramatically reduced by extending the period of H-treatment.