Formation of a dense nanocrystalline Si array on an insulating layer by laser irradiation of ultrathin amorphous Si films

A new approach to achieve a dense nanocrystalline Si array on an insulating layer was demonstrated. It was found that a single layer of nanocrystalline Si array can be formed by using KrF pulsed excimer laser irradiation on ultrathin hydrogenated amorphous silicon films (4-20 nm) followed by thermal annealing. The area density of the nanocrystalline Si formed is as high as 1011 cm−2, the lateral size is around 10 nm, and the height is about 2-4 nm when a suitable laser irradiation fluence was used. By controlling the laser irradiation fluence and the initial a-Si:H film thickness, the grain size, density and crystallization fraction can be changed accordingly.