Method for making lcd device in which gate insulator of tft is formed

Abstract

An active matrix liquid crystal display device, with a plurality of thin-film transistors provided over a glass substrate each including an anodized oxide film of aluminum gate electrode, in which transparent pixel electrodes are formed in the same plane as the gate electrodes between the glass substrate and amorphous silicon islands over which source and drain electrodes are provided. In such a device structure, in which the spacing between the ITO and the gate electrode can be compacted while ensuring that there are no short-circuits effected between the ITO layer and gate electrode during the manufacture of the LCD device, the gate electrode and, therefore, also the plate (lower) electrode of the capacitor Cadd are first formed, followed by the formation of the AOF layer over the gate electrode and over the plate electrode of the capacitor, respectively. Subsequently, the ITO pixel electrode is formed on the same plane as that of the first conductive layer, corresponding to the gate electrode and plate electrode of capacitor Cadd, and is followed by the formation of a relatively thicker second insulating layer, for example, a nitride insulating layer, on the first insulating layer, namely, the anodized oxide film, and on the pixel electrode. In accordance with this scheme, furthermore, the first insulating layer is formed by anodizing the metal layer constituting the first conductive layer.