Low-temperature polycrystalline silicon (poly-Si) is of increasing interest for the display on glass. Among several techniques for the low-temperature poly-Si the Ni-mediated crystallization of amorphous silicon (a-Si) is promising one. We studied the crystalline orientation of the disk-shaped grains in the poly-Si formed by Ni-mediated crystallization of a-Si using a SiO2 nanocap by electron backscattered diffraction measurements. A SiO2 nanocap layer was formed by 02 plasma treatment on a-Si and an ultrathin Ni layer was deposited on the nanocap. It was heated in a UV scan system for crystallization. The Ni atoms in a-Si diffused through the nanocap and formed NiSi2 crystallites. Disk-shaped grains were then grown from these nuclei. The size of disk-shaped grains in poly-Si increases from similar to6 to similar to20 mum when the thickness of nanocap on a-Si changes from 2.4 to 3.2 nm. On the other hands without the nanocap layer, its size is similar to3.5 mum. The crystalline quality of poly-Si is improved by introducing a nanocap layer, which is due mainly to the increase of the grain size. (C) 2004 American Vacuum Society.