Pure-shear mode BAW resonator consisting of (112̄0) textured AlN films

In-plane and out-of-plane oriented (11 2macr 0) textured AlN thin films are attractive for shear mode piezoelectric devices and sensors, such as FBAR and SH-SAW devices. It is proposed here that highly oriented (11 2macr0) AlN thin films can be fabricated using ion beam sputter-deposition system with grazing incidence to the substrate surface. Full-width-at-half-maximum (FWHM) values of the omega-scan rocking curve and phi-scan profile curves of the (11 2macr2) X-ray diffraction poles were measured to be 4.6deg and 23deg, respectively. Shear-mode high-overtone acoustic resonator (HBAR) with (11 2macr0) textured AlN film excited pure-shear wave without any longitudinal wave excitation. New device structure is expected because this film can be deposited on various substrates and curved surfaces.