Low temperature polycrystalline silicon with single orientation on glass by blue laser annealing

Abstract

We report the achievement of low-temperature polycrystalline silicon (LTPS) thin-films with a single orientation on glass by using continuous wave blue laser annealing (BLA) of amorphous silicon (a-Si). The BLA is administered in multiple shots and with increasing number of shots, grain size increases and all grains follow a single orientation. Because the absorption coefficient of a blue laser (BL) in poly-Si is less than that in a-Si, the amount of the un-melted Si at the bottom is gradually reduced with increasing number of shots, resulting in near complete melting of the whole Si layer. In this study, irradiation of a 150-nm-thick a-Si film with 200 BL (445nm) shots achieves a poly-Si film having an average grain size of about 4μm and single orientation in the (100) direction.