Ivira Brice, Benech Phippippe, Fillit René, Ndagijimana Fabien, Ancey Pascal, Parat Guy
Institute of Microelectonics, Electromagnetism and Photonics, INPG/UJF, CNRS, Grenoble, France.
IEEE Trans Ultrason Ferroelectr Freq Control. 2008 Feb;55(2):421-30. doi: 10.1109/TUFFC.2008.660.
This paper deals with the temperature dependence of electrical and physical features of various kinds of solidly mounted resonators (SMR). The presented bulk acoustic wave (BAW) devices are designed for the 2 GHz application. The temperature coefficient of frequency (TCF) is determined from measurements well above the temperature range defined for wireless telecommunication system specifications. Therefore, evolution of electromechanical coupling factors and quality factors at resonance and antiresonance are also monitored. Results of characterizations show the trend for a subsequent theoretical temperature compensation study by using analytical modeling. To improve accuracy of modeling, an attempt to extract temperature dependence of dielectric permittivity epsilon(33) and piezoelectric coefficient e(33) is made. Finally, a well-known analytical model is modified to take into account the temperature dependence of length, density, stiffness coefficient, dielectric permittivity, and piezoelectric coefficient. Modeling highlights the need to deposit a material with positive temperature coefficient of stiffness on the top electrode. Realistic thickness of such a layer is determined. At the same time, it is necessary to adjust piezoelectric and electrode thin film thicknesses for simultaneously keeping a constant antiresonance frequency, reaching a zero temperature coefficient of frequency for antiresonance, and minimizing the decrease in the coupling factor because of the mass-loading deposition.
本文探讨了各种固态安装谐振器（SMR）的电学和物理特性与温度的关系。所展示的体声波（BAW）器件是为2 GHz应用设计的。频率温度系数（TCF）是在远高于无线通信系统规范所定义的温度范围的测量中确定的。因此，还监测了谐振和反谐振时机电耦合因子和品质因数的变化。表征结果显示了通过解析建模进行后续理论温度补偿研究的趋势。为提高建模精度，尝试提取介电常数ε(33)和压电系数e(33)的温度依赖性。最后，对一个著名的解析模型进行修改，以考虑长度、密度、刚度系数、介电常数和压电系数的温度依赖性。建模突出了在顶部电极上沉积具有正刚度温度系数的材料的必要性。确定了这种层的实际厚度。同时，有必要调整压电和电极薄膜的厚度，以同时保持恒定的反谐振频率、使反谐振的频率温度系数为零，并使由于质量负载沉积导致的耦合因子下降最小化。
