Papers by Author: Sean Wu

Abstract: In this study, we propose an approach to compute the parasitic parameters of an surface acoustic wave (SAW) resonator, which is fabricated on 36o YX lithium tantalate substrate using standard semiconductor processes. The measured admittances of the SAW resonator are used to calculate the corresponding counter parts by applying the Kramers-Kronig relations. The parasitic parameters are then retrieved by minimizing the errors between the calculated and measured admittances.

Abstract: The thin film of (103)-oriented aluminum nitride (AlN) is an attractive piezoelectric material for the applications in film bulk acoustic wave resonator (FBAR) devices. Due to the bulk acoustic wave (BAW) properties of (103) oriented AlN films, it can excite a quasi-shear mode (velocity = 5,957 m/s, K² = 3.8%) that can be used for FBAR liquid sensor and even loss less than the FBAR device with (002) oriented AlN films. In this research, the (103) oriented AlN films were successfully deposited onto (100) silicon substrate by radio frequency (RF) magnetron sputtering. Different sputtering pressures (1m torr, 3m torr, 5m torr, and 7m torr) were discussed in this experiment process. Comparisons were made on their crystalline structures with X-ray diffraction (XRD) and the surface morphologies was investigated by the atomic force microscopy (AFM). The result exhibited the optimal sputtering pressure is 5m torr. The optimal (103) oriented AlN films have the strongest XRD intensity, the smallest full width at half maximum (FWHM) value (0.6°), the largest grain size (15.78nm) and the smooth surface roughness (Ra=3.259nm).