The Characterization of Al2O3 Prepared by Anodic Oxidation

Abstract

Aluminum is a good candidate of low resistivity metal as a gate electrode metal and a gate bus-line metal in amorphous silicon thin-film transistor of liquid crystal display. But it easily brings about hillocks and whiskers during the heat process, and causes defects. Al₂O₃ formed on aluminum layer is expected to work as a protective layer against hillock formation. The formation of Al₂O₃ is developed by anodic oxidation method. The electrical characteristics of Al₂O₃ layers formed at constant DC anodic bias or constant DC current density were investigated. The optimal growth condition of Al₂O₃ has been developed. In addition, the double-layer of Al₂O₃/SiN is also shown to be sufficiently protective against hillock formation.