Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators Through Laser Acoustic Imaging. 2006 IEEE International Ultrasonics Symposium.

Telschow, K. L. ; Larson, J. D.

Technical Information Center Oak Ridge Tennessee

关键词: Acoustic resonators;    Lasers;    Imaging techniques;    Semiconductor films;    Surface acoustic wave devices;   

RP-ID  :  DE2007911645

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Film Bulk Acoustic Resonators are useful for many signal processing applications. Detailed knowledge of their operation properties are needed to optimize their design for specific applications. The finite size of these resonators precludes their use in single acoustic modes; rather, multiple wave modes, such as, lateral wave modes are always excited concurrently. In order to determine the contributions of these modes, we have been using a newly developed full-field laser acoustic imaging approach to directly measure their amplitude and phase throughout the resonator. This paper describes new results comparing modeling of both elastic and piezoelectric effects in the active material with imaging measurement of all excited modes. Fourier transformation of the acoustic amplitude and phase displacement images provides a quantitative determination of excited mode amplitude and wavenumber at any frequency. Images combined at several frequencies form a direct visualization of lateral mode excitation and dispersion for the device under test allowing mode identification and comparison with predicted operational properties. Discussion and analysis are presented for modes near the first longitudinal thickness resonance (approximately 900 MHz) in an AlN thin film resonator.