Orientation control of location-controlled Si crystal grain by combining Ni nano-imprint and excimer laser annealing with Si double-layer process

A new method of controlling the location and orientation of Si crystal grains by combining metal (Ni) nano-imprint and excimer laser annealing (ELA) using a double-layered Si thin-film structure was successfully demonstrated. Ni nano-imprint at the surface of the first amorphous silicon (a-Si) film (25 nm thick) was used for the purpose of creating {111}-oriented Sicrystal nuclei which act as the seed for the subsequent crystallization using ELA. The annealing to form nuclei at the imprinted sites was carried out at temperatures below 450 °C. After removal of Ni, the second a-Si film layer (75 nm thick) was deposited. XeCl-laser-based ELA of the sample resulted in the formation of approximately 2 μm sized Si crystal grains at controlled positions. Electron back-scattering pattern (EBSP) analysis showed that the surface-normal orientation of all the location-controlled grains was {111}, and that 87% of the boundaries in the grain interiors were the coincidence site lattice (CSL) boundaries.