DOUBLE-ACTIVE-LAYER STRUCTURE WITH A POLYSILICON LAYER AND A MICROCRYSTALLINE SILICON LAYER, METHOD FOR MANUFACTURING THE SAME AND ITS APPLICATION

摘要

A first amorphous silicon layer is formed over a substrate and a second amorphous silicon layer is formed over the first amorphous silicon layer. When a laser annealing process is performed, the second amorphous silicon layer absorbs more laser light than the first amorphous silicon layer does. The first amorphous silicon layer crystallizes into a microcrystalline silicon layer and the second amorphous silicon layer crystallizes into a polysilicon layer. During the laser annealing process, light interference between the first amorphous silicon layer and an underlying buffer layer is eliminated owing to that the second amorphous silicon layer absorbs more laser light. The laser fringe is eliminated. The microcrystalline silicon layer with better crystalline uniformity can serve as an active layer for TFTs in the display area of an OLED display to improve its illumination uniformity.