Abstract
When AlN thin films are applied to surface acoustic wave (SAW) devices, c-axis oriented films and a-axis oriented films are necessary for the longitudinal wave and transversal wave, respectively. In general, when AlN thin films are prepared by sputtering and ion plating methods, the crystallographic orientation is dominantly c-axis; it is difficult to prepare films with an a-axis orientation.
In this study, AlN thin films were prepared by a new PVD method: the electron shower. It was found that a-axis orientation films could be prepared readily. The crystallographic orientation varied from a-axis to c-axis when the substrate voltage was changed from +20V to -400V. A high hardness (Hv 2200), high electrical resistivity (1013Ωcm) film was obtained at -200V.
