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 AIN, polycrystalline AlN, ha ve been made by a sputter method at room temperature. AES, XPS, XRD an d TEM have been used to investigate the composition, the ratio of meta llic Al to nitrided Al, the structure and two-phase coexistence morpho logy for various Al-N films respectively, which have been found to be strongly dependent on the total sputtering pressure and content of nit rogen gas. The Al-N films obtained can be classified into three catego ries, that is, the Al-rich metallic films with a positive temperature coefficient of resistivity (TCR), the Al-rich semiconducting films wit h a negative TCR and the stoichiometric insulating films. The current- voltage curves of Al-rich Al-N films are presented. The metallic condu ction and semiconductor conduction are two main electrical conduction mechanisms for the various Al-rich Al-N films.