Optimization of the sputtering deposition parameters of highly oriented piezoelectric AlN films

AlN films have been successfully deposited by reactive sputtering technique on silicon substrates with different interface layers. Uniform, crack free, c-axis oriented, highly adhesive films have been obtained in a thickness range between 1 and 5.6 /spl mu/m. Measurements of the d/sub 33/ piezoelectric strain constant have been performed in order to evaluate the piezoelectric characteristics of the films. X-ray diffraction measurements (XRD) have been performed to investigate the crystal structure and the crystallographic orientation of the films, in order to optimize the deposition process parameters and to study the influence of the substrate on the AlN polycrystals orientation.