Effects of crystallization mechanism on the electrical characteristics of green continuous-wave-laser-crystallized polycrystalline silicon thin film transistors

Abstract

Thin film transistors (TFTs) with amorphous silicon films crystallized via continuous-wave green laser at a wavelength of 532 nm exhibit very different electrical characteristics in various crystallization regions, corresponding to the Gaussian energy density distribution of the laser beam. In the center region subjected to the highest energy density, the full melting scheme led to the best crystallinity of the polycrystalline silicon film, resulting in the highest field-effect mobility of 500 cm2 V−1 s−1. In contrast, the edge region that resulted in solid phase crystallization exhibited the worst mobility of 48 cm2 V−1 s−1 for the polycrystalline silicon TFTs.