Patent ID: 7339188

Claim:
A polycrystalline silicon film on a buffer layer that is on a substrate, the polycrystalline film containing nickel metal of which density ranges 2×10 17 to 5×10 19 atoms/cm3, and an electrical conductivity activation energy between 0.53 eV and 0.71 eV, the polycrystalline silicon film comprising a plurality of needle-shaped silicon crystallites; metal electrodes on opposite sides of the polycrystalline silicon film; and an electric field substantially across the polycrystalline silicon between the metal electrodes, wherein the polycrystalline silicon film is formed by crystallizing an amorphous silicon film containing nickel metal by a thermal treatment carried in a temperature of 400 to 500° C. and due to the electric field, and wherein the needle-shaped silicon crystallites are formed by movement of a silicide of the metal.