Heat Resistance of Ga-Doped ZnO Thin Films for Application as Transparent Electrodes in Liquid Crystal Displays

The electrical characteristics and residual stresses in three types of Ga-doped ZnO (GZO) films formed using a reactive plasma deposition system (type 1 film) and a magnetron sputtering system utilizing dc power (type 2 film) or (rf) power (type 3 film) were compared from the viewpoint of heat resistance as a function of the thermal process for liquid crystal display (LCD) fabrication. The resistivity of the as-formed GZO films prepared at can be ordered as . However, the heat resistance of the films was ordered as . Thus, the GZO films prepared by magnetron sputtering utilizing power did not satisfy the condition for transparent electrodes for LCDs in terms of heat resistance against the ca. processing step. LCD panels (3 in.) using the GZO transparent electrodes on the red-green-blue color filters were fabricated for demonstrating the feasibility of using this material as an electrode.