Structural and electrical properties of polycrystalline silicon produced by low-temperature Ni silicide mediated crystallization of the amorphous phase

Abstract

Amorphous silicon (a-Si) film was crystallized at 500 °C, using a thin Ni layer. The crystallization proceeds by the migration of NiSi2 precipitates through the a-Si network. The crystallization kinetics change with the density of NiSi2 precipitates on the a-Si. The high density of NiSi2 precipitates, formed at a thick Ni layer, leads to vertical migration of the NiSi2 precipitates. With decreasing Ni thickness on a-Si, the spacing between NiSi2 precipitates increases and leads to lateral growth of crystallites. The room temperature conductivity is around 10−5 S/cm, and the activation energy is around 0.49 eV when the average Ni thickness is 24 Å or less. The sheet resistance of the ion-doped, poly-Si film decreases with the average Ni thickness because the crystalline quality improves as the Ni thickness is decreased.