Crystallization to polycrystalline silicon films by underwater laser annealing and its application to thin film transistors

We performed crystallization of an amorphous silicon by laser irradiation in flowing deionized-water where Nd: YAG THG laser (wave length = 355 nm) was used for annealing. As the results, we demonstrated that the underwater laser annealing (WLA) leads to giant- and uniform-grain growth as compared to laser annealing in air (LA). It is thought that the homogenization of the temperature distribution within the Si films enhances grain growth. In addition, we successfully fabricated the poly-Si TFTs with the use of WLA poly-Si as the channel layer. The output and the transfer characteristics were clearly obtained, and thus we succeeded in the TFT operation.