Disclosed is a method for fabrication of a liquid crystal display with improved optical transmission, which includes sequentially forming a first oxide film, a silicon film, and a second oxide film on a semiconductor substrate, selectively etching the silicon film and the second oxide film to expose the first oxide film, forming a oxynitride film on at least the silicon film, forming a polysilicon layer over the oxynitride film, selectively etching the polysilicon layer to form a top electrode, forming an insulating film on and/or over the substrate, including the top electrode, and forming metal wirings on outer regions of the top electrode.