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-N-2) 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-N-2) 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 10(11) to 10(12) Omega-cm at moderate electric fields. The application of these films in piezoelectric based micro-electro-mechanical systems is discussed. (C) 2011 Elsevier B.V. All rights reserved.