Crystal growth characterization of polycrystalline silicon films obtained by hot-wire chemical vapour deposition

Polycrystalline silicon (poly-Si) films were obtained at moderate temperatures (280-500 degrees C) from a mixture of silane and hydrogen in a hot wire CVD reactor. SEM and TEM results revealed a columnar growth of poly-Si grains with a preferential orientation of the crystals perpendicular to the substrate surface along the [110] direction. Plan view examinations along the [110] axis revealed a needled shape of the crystals (0.3-1 mu m) with the largest axis randomly distributed on the plane. The high quality of the polycrystalline samples obtained makes the hot-wire technique very promising.