Conde Janine, Muralt Paul
Department of Materials Science, Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland.
IEEE Trans Ultrason Ferroelectr Freq Control. 2008;55(6):1373-9. doi: 10.1109/TUFFC.2008.800.
The behavior of {f111g}-textured Pb(Zr(0.53Ti0.47O3) (PZT) deposited by the sol-gel technique in thin film bulk acoustic resonators (TFBAR's) was investigated at a resonance frequency of about 1 GHz. The resonators were fabricated on Si wafers using deep silicon etching to create a membrane structure and using platinum as top and bottom electrodes. The best response of the resonators was observed at a bias voltage of -15 kV/cm with values of about 10% for the coupling constant and about 50 for the quality factor. This voltage corresponds to optimal values of piezoelectric constant d33 and dielectric constant measured as a function of the electric field. The influence of a bias voltage on the resonance frequency, antiresonance frequency, and coupling constant were observed. Both the resonance and antiresonance frequency show a hysteretic change with applied bias. This effect can be used to shift the whole band of a filter by applying a voltage. The TFBAR structure also allowed us to extract values for materials parameters of the PZT film. Dielectric, piezoelectric, and elastic properties of the f111g-textured PZT film are reported and compared to direct measurements and to literature values.
研究了通过溶胶-凝胶技术沉积在薄膜体声波谐振器（TFBAR）中的{111}织构Pb(Zr(0.53Ti0.47)O3)（PZT）在约1 GHz共振频率下的行为。谐振器是在硅片上制造的，采用深硅蚀刻来创建膜结构，并使用铂作为顶部和底部电极。在-15 kV/cm的偏置电压下观察到谐振器的最佳响应，耦合常数约为10%，品质因数约为50。该电压对应于作为电场函数测量的压电常数d33和介电常数的最佳值。观察到偏置电压对共振频率、反共振频率和耦合常数的影响。共振频率和反共振频率都随施加的偏置呈现滞后变化。通过施加电压，这种效应可用于移动滤波器的整个频段。TFBAR结构还使我们能够提取PZT薄膜的材料参数值。报告了{111}织构PZT薄膜的介电、压电和弹性特性，并与直接测量值和文献值进行了比较。
