Polycrystalline silicon thin film transistors fabricated by employing selective self ion-implantation and excimer laser annealing

We propose a new excimer laser annealing method to obtain reproducible poly-Si films with low defect densities and large grains by employing combination of selective self ion-implantation and excimer laser annealing. Selective self ion-implantation is utilized to form artificial nucleation seeds in an a-Si film prior to excimer laser annealing. By exploring a specifically designed implantation mask, we could control the grain boundary location in the poly-Si film and could enlarge the grain size to the order of micrometers without any other treatment. We observed the grain boundary distribution in the excimer-laser-annealed film by using transmission electron microscopy (TEM) and the crystallinity of the enlarged grains by using TEM diffraction images.