Piezoelectric Lateral-Extensional Mode Resonators With Reconfigurable Electrode and Resonance Mode-Switching Behavior Enabled by a VO₂ Thin-Film
Piezoelectric Lateral-Extensional Mode Resonators With Reconfigurable Electrode and Resonance Mode-Switching Behavior Enabled by a VO₂ Thin-Film
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压电横向延伸模式谐振器，具有可重构电极和由 VO™ 薄膜实现的谐振模式切换行为
DOI：
10.1109/tuffc.2022.3156845
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Wang, Jing
中科院分区：
文献类型：
--
作者：
Liu, Ting Hung;Han, Xu;Pastrana, Juan;Sepulveda, Nelson;Wang, Jing
本文提出了第一个双端口横向延伸模式的氧化锌（ZnO）压电谐振器与可重构的底部电极，使嵌入二氧化钒（VO 2）薄膜。VO 2的绝缘体到金属的相变由基板加热触发，基板加热转化为电场模式和压电转换模式振动的突变，从而允许压电谐振器在特定频率下进行模式切换。有限元法（FEM）分析用于对宽带频率响应进行建模，同时在20 °C和95 °C之间的温度范围内测量相应双端口谐振器的频率特性，特别关注88和148 MHz的两个谐振。通过利用VO 2薄膜在加热/冷却循环过程中的滞后行为，观察到电容馈通和谐振信号电平的变化，这是由于VO 2在其相变过程中电导率的突然变化。在加热循环期间，在88 MHz处的谐振的独特开关-接通行为在70 °C处开始，而开关-关断转变在冷却循环期间在60 °C处开始。另一方面，当温度从20 °C增加到60 °C时，对于148 MHz处的谐振，观察到插入损耗和谐振频率分别降低12 dB和0.28MHz。同时，当温度从60 °C升高到95 °C时，观察到了0.42 MHz的共振频率增加，这可以归因于VO 2从单斜相到金红石相的相变。插入损耗和谐振频率的磁滞回线表明从单斜（绝缘体）相和金红石（金属）相的相变的不同临界温度，反之亦然。频率的温度系数的实质性变化可以在很大程度上归因于由VO 2相变启用的电极重新配置。
This article presents the first two-port lateral-extensional mode zinc oxide (ZnO) piezoelectric resonator with a reconfigurable bottom electrode that is enabled by embedding a vanadium dioxide (VO2) thin film. The insulator-to-metal phase transition of VO2is triggered by substrate heating that translates to abrupt changes in electric field patterns and piezoelectrically transduced modal vibrations, thus allowing mode-switching of piezoelectric resonators at specific frequencies. Finite element method (FEM) analysis was used to model the broadband frequency response, while frequency characteristics of the corresponding two-port resonator were measured over a temperature range between 20 °C and 95 °C with a specific focus on two resonances at 88 and 148 MHz. By leveraging the hysteretic behavior of VO2thin film during a heating/cooling cycle, a change in both the capacitive feedthrough and resonance signal levels was observed, due to the abrupt change in the conductivity of VO2during its phase transition. The unique switch- ON behavior of the resonance at 88 MHz starts at 70 °C during the heating cycle, while the switch- OFF transition begins at 60 °C during the cooling cycle. On the other hand, when the temperature is increased from 20 °C to 60 °C, a decrease in the insertion loss and resonance frequency of 12 dB and 0.28 MHz, respectively, were observed for the resonance at 148 MHz. Meanwhile, a resonance frequency increase of 0.42 MHz was observed during a temperature increase from 60 °C to 95 °C, which can be ascribed to VO2phase transition from monoclinic to rutile phase. The hysteresis loops for insertion loss and resonance frequency indicate a different critical temperature for phase transition from the monoclinic (insulator) phase and rutile (metallic) phase and vice versa. The substantial variation in the temperature coefficient of frequency can be largely ascribed to electrode reconfiguration enabled by VO2phase transition.