Analysis and Fabrication of AlN Thin Film Bulk Acoustic- Wave Resonators

• Main Authors: Yung-Hung Liu, 劉永宏
• Other Authors: Bing-Jin Li
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/77127960536014589149

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 93 === 　The paper presents the analysis and fabrication of thin film bulk acoustic wave resonator(FBAR). The FBAR structures are made of piezoelectric aluminum nitride layers which are fabricated on silicon wafer using the technique of RF magnetron sputtering of . Aluminum and platinum are the top and bottom electrodes. A longitudinal bulk wave can be excited within the highly C-axis-oriented piezoelectric AlN film and reflects from the surface boundaries of the AlN membrane. Similar to an acoustical cavity, the FBAR structure exhibits parallel and series electrical resonance responses, corresponding to even- and odd-order modes, and decreasing the thickness of the AlN film increases the resonance frequency. The results show that the shape of top electrodes can affect the resonance of the FBAR structure with spurious modes.　Moreover, less symmetric electrodes can inhibit spurious resonance modes. Effects of resonator size on input impedance are also discussed. The Modified Butterworth-Van Dyke model basing on the fundamental resonant frequency response of resonators is used for the analysis of the structure. The resonant frequencies, effective electromechanical coupling coefficients( ) and quality factors both from the modeling and experimental measurements will be compared and discussed.