Design and Fabrication of Wafer Level Dual-Band Thin Film Bulk Acoustic Resonator Filters
This paper describes the design and fabrication of dual-mode film bulk acoustic resonator (TFBAR) devices to construct wafer level dual-band T-ladder type filters. The T-ladder type filters is selected in this study for its high quality and simple fabrication processes. The c-axis-tilted ZnO thin films to obtain dual-mode TFBAR devices have been investigated. The characteristics of dual-mode TFBAR devices appeared by off-axis deposition of ZnO thin films with the RF magnetron sputtering. The top and bottom electrodes consisted of titanium (Ti) and platinum (Pt) layers are deposited by dual-gun DC sputtering system. The pass-band width of filters is controlled by the mass loading on the dual-mode. The frequency response is measured using an HP8720 network analyzer and a CASCADE probe station.
W. T. Chang et al., "Design and Fabrication of Wafer Level Dual-Band Thin Film Bulk Acoustic Resonator Filters", Advanced Materials Research, Vols. 308-310, pp. 201-208, 2011