A method for fabricating an array substrate includes: forming a first metal layer on a base substrate; forming an insulating layer of a silicon-containing organic material on the first metal layer; forming a second metal layer on the insulating layer; patterning the second metal layer by adopting an oxygen ion etching process to partially cover the insulating layer; and forming a silicon oxide layer, by the oxygen ion etching process, on a surface of the insulating layer not covered by the second metal layer.