微机电系统谐振器原子力显微镜探针设计与检测

为克服既有原子力显微镜（AFM）悬臂式探针的谐振频率难以超过3.5 MHz，Q值低、成像速度低及在液体中成像效果欠佳等缺点，设计并制作了一种基于微机电系统（MEMS）谐振器的I2形探针，并成功实现了成像实验。为更进一步提高I2形探针的力灵敏度，从结构设计和检测方法入手，对原有探针进行改进。设计了简单有效的电阻差分检测方法，成功去处了输入端与输出端的耦合现象；采用局部离子注入的方法，提高了压阻敏感的传输效率。实验结果显示，在输入信号相同的条件下，改进后探针的输出信号与原有探针相比，输出信号得到了明显提高。计算结果表明，采用新方法制作的探针可使力灵敏度提高10倍以上。

Design and measurement of AFM probe based on MEMS resonator

In order to effectively prompt the resonance frequency and the quality factor of atomic force microscope (AFM) probes simultaneously, a novel oscillating probe based on a I2 shaped MEMS resonator was conceived, designed, fabricated and evaluated. To further improve the imaging capability of this kind of probe, structure design and measurement improvements were studied and presented in this work, including new detection scheme based on simple differential measurement and using locally doped piezoresistors at maximum strain locations. Experimental results showed that with these improvements, the feedthrough coupling effect between driving and sensing is effectively eliminated and the measurement sensitivity is improved by at least 10 times.