Disk-Shaped Crystal Grain in Poly-Si Film Prepared by Excimer Laser Annealing

The effects of hydrogen in a-Si film on the growth of disk-shaped grain formed by excimer laser annealing (ELA) were investigated. For the energy density of 2500 J/m2, the disk-shaped grain was not observed by scanning electron microscope. On the other hand, at the energy density of 3000 J/m2, the disk-shaped grain was observed. The size of textured grain increased with increasing shot number. The area density of disk-shaped grain was constant in spite of increment of the shot number. In addition, the shot-number dependence of strain and crystal orientation differed between poly-Si films with and without disk-shaped grain. It is considered that the nucleation and growth of disk-shaped grain were suppressed by hydrogen. It is expected that the position and density of the disk-shaped grain can be controlled by hydrogen in a-Si film.