Characterization of aluminum surface layers produced by ion implantation

Abstract

The surface properties such as depth profile, chemical bond, and structure, and electrical properties of oxide and nitride layers in aluminum produced by high dose implantation of oxygen and nitrogen ions were investigated. High dose of oxygen (4×10¹⁸ions/cm²) and nitrogen (2×10¹⁸ions/cm²) molecule ions were implanted into polycrystalline and single crystal aluminum sheets using low current densities of 150keV at room temperature. The implanted layers were characterized by means of AES, XPS, X-ray and transmission electron diffraction, transmission electron microscopy, and IR spectroscopy. The electrical resistivity and breakdown electric field strength of oxide and nitride layers were measured by current-voltage characteristics. It was found that high dose oxygen ion implantation produces microcrystalline γ-Al₂O₃, whereas implanted nitrogen leads to polycrystalline or single crystal AlN layers at room temperature without any thermal annealing, and it is possible to form electrically insulating layers in aluminum using this technique.