Patent ID: 6727122
Filing Date: 2004-04-27
Classification: H01L,Y10S

Abstract:
A method of forming a polycrystalline silicon active layer for use in a thin film transistor, comprising:forming a buffer layer over a substrate; forming an amorphous silicon layer over the buffer layer; applying a catalytic metal to a surface of the amorphous silicon layer; crystallizing the amorphous silicon layer having the catalytic metal thereon into a polycrystalline silicon layer; forming an island pattern on the polycrystalline silicon layer, thereby defining an active region underneath in the polycrystalline silicon layer; applying n-type ions to the polycrystalline silicon layer and then heat-treating the polycrystalline silicon layer to remove the catalytic metal from the active region underneath the island pattern; patterning the polycrystalline silicon layer using the island pattern as a mask to form an active layer and to expose a surface of the adjacent buffer layer; removing the island pattern from the active layer using an etchant; and etching the exposed surface of the buffer layer to remove residual catalytic metal left on the buffer layer.