Structures and Electric Characteristics of Al–N Thin Films Prepared by RF Sputtering

A variety of Al-rich Al–N and stoichiometric AlN films with different structures, including Al+AlN, amorphous AlN, polycrystalline AlN, have been made by a sputter method at room temperature. AES, XPS, XRD and TEM have been used to investigate the composition, the ratio of metallic Al to nitrided Al, the structure and two-phase coexistence morphology for various Al–N films respectively, which have been found to be strongly dependent on the total sputtering pressure and content of nitrogen gas. The Al–N films obtained can be classified into three categories, that is, the Al-rich metallic films with a positive temperature coefficient of resistivity (TCR), the Al-rich semiconducting films with a negative TCR and the stoichiometric insulating films. The current-voltage curves of Al-rich Al–N films are presented. The metallic conduction and semiconductor conduction are two main electrical conduction mechanisms for the various Al-rich Al–N films.