Deposition and characterization of c-axis oriented aluminum nitride films by radio frequency magnetron sputtering without external substrate heating

Aluminum nitride (AlN) films were deposited on a variety of substrates (glass, Si, oxidized Si, Al–SiO2–Si, Cr–SiO2–Si, and Au–Cr–SiO2–Si) by radio frequency (RF) magnetron sputtering using an AlN target. The films were deposited without external substrate heating. The effect of RF power, ambient gas (Ar and Ar–N2) and sputtering pressure on deposition rate and crystallinity were investigated. The structure and morphology of the films were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy techniques. These investigations revealed that the AlN films prepared in mixed gas ambient (Ar–N2) were highly c-axis oriented with moderate surface roughness on all the substrate. A strong IR absorption band was observed around 670 cm− 1 which confirms the presence of Al–N bond in the film. The dc resistivity of the films was measured to be in the range of 1011 to 1012 Ω-cm at moderate electric fields. The application of these films in piezoelectric based micro-electro-mechanical systems is discussed.