温度变化对微梁谐振频率的影响

双层材料微梁是一种常见的高灵敏度微梁传感结构，温度变化会使微梁发生弯曲形变并改变微梁的谐振频率．研究了微梁谐振频率与其构成材料的杨氏模量E和热膨胀系数a的关系、以氮化硅上沉积了不同厚度金膜的双层微梁结构为对象，通过在原子力显微镜AFM上的实验获得了295～325K范围内微梁的弯曲形变和谐振频率分别与温度变化的关系曲线．对实验结果的分析表明，构成微梁两种材料热膨胀系数的差异会引起微梁的非线性形变和谐振频率的非线性偏移，且主要在温度变化范围小于5K时起作用；在295～325K时两种材料杨氏模量随温度的变化会引起微梁谐振频率的线性偏移．同时，提出了相应的微梁应用建议，以保证在环境温度有变化的应用场合下双层材料微梁仍具有较高的测量精度.

Resonant Drift of Microcantilever Caused by Temperature Variation

Microcantilevers with bimaterial layers are commonly used for ultra-high sensitivity measurement. Both the deflection and the resonant frequency of a microcantilever vary with the change of temperature. The relationship of the resonant frequency shift of mierocantilever with Young modulus of the bimaterial and thermal expansion coefficient（TEC） were studied theoretically. Silicon nitfide microcantilevers with gold fihn of different thickness were fabricated. These bimaterial microcantilevers＇ responses of deflection and resonant frequency shift to temperature variation were obtained on AFM. The results showed that the TEC difference of the bimaterial induced nonlinear deflection and resonant frequency shift, and it had the effect only when temperature variation were in a small range （ 〈 5 K）. While the thermal dependence of Young＇s modulus caused a linear resonant frequency shift in the whole 295-325 K temperature range. Suggestions were given to keep high measurement accuracy when applying bimaterial microcantilevers in variable-temperature circumstances