Characterization of (Al, Si)N films deposited by balanced magnetron sputtering

Hard and transparent nanocomposite (Al, Si)N films are attractive for optical applications. In this paper, experimental results will be reported on nanocomposite (Al, Si)N films prepared by balanced magnetron sputtering. Microstructure and properties of the films were systematically characterized as a function of Si content of the films. It is shown that the (Al, Si)N films are transparent and exhibit no absorption in a wide range of wavelengths from ~ 0.3 to ~ 9 µm, i.e. from ultraviolet to mid-infrared region. Maximum hardness exceeding 25 GPa has been obtained when the Si content of the films is above 25 at.% and the microstructure of the films undergoes a transformation from nanocrystalline to amorphous states. It is demonstrated that the microstructure detail of the films is different, as compared with that of the films prepared by using unbalanced magnetron sputtering, and the reasons for this discrepancy is discussed.