New excimer-laser-crystallization method for producing large-grained and grain boundary-location-controlled Si films for thin film transistors

Based on the previously elucidated super lateral growth phenomenon, we have developed an excimer-laser-crystallization method that produces large-grained and grain-boundary- location-controlled Si films on SiO2 and which possesses a wide processing window. For the set of experiments reported in this letter, a patterned SiO2 capping layer on top of Si films is utilized as an anti-reflective coating in order to induce artificially controlled super-lateral growth in the film upon being irradiated with a single excimer laser pulse. For a simple SiO2 stripe pattern, the occlusion among the laterally and directionally solidifying grains permits the eventual development of elongated parallel grains with a single perpendicular grain boundary which is localized in the middle of the completely melted regions, provided that the width of the completely molten region is sufficiently narrow so as to avoid the nucleation of solids in the supercooled liquid.