Analytical and experimental study on the second harmonic mode response of a bulk acoustic wave resonator
Year: 2010
Type: article
Abstract: A one-dimensional Mason model is employed to investigate the second harmonic mode response of a multilayer composite film bulk acoustic resonator (FBAR), particularly the dependence of the effective coupling coefficient ( K 2 t , eff ) on material properties and relative position in the acoustic stack. The simulation results for AlN-based FBAR with electrode layer having relatively low acoustic impedance and additional temperature compensation layer reveals that the maximum values of K 2 t , eff are obtained with a thickness ratio (between the non-piezoelectric layer and piezoelectric layer) that is close to its acoustic velocity ratio. The fundamental mode and second harmonic mode operation of an FBAR are compared. The maximum achievable K 2 t , eff is comparable (5.39% versus 5.16%) for the temperature compensated FBAR (with Mo as electrodes) operating at fundamental and second harmonic modes. However, the trimming-mass and crossover temperature sensitivities of the second harmonic mode are lower, indicating its potential advantage over the fundamental mode for high frequency applications above 2 GHz (such as filters, low phase noise temperature stable oscillator applications). Experimental results on a ZnO-based FBAR (Al/ZnO/Al/Si x N y ) operating around 5 GHz with various thicknesses of ZnO and Si x N y show good agreement with numerical modeling.
Authors: Wei Pang, Hao Zhang, Richard C Ruby, Hongyu Yu, Eun Sok Kim
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
Award: G1037014486
OpenAlex ID: W2013250065