AFM微悬臂梁探针弹性常数各种标定方法的比较与分析

摘要

Micro-cantilever probe is an important force sensor in atomic force microscope (AFM) based micro-or nano-Newton force measurement. The accuracy of the spring constant is of great significance to the reliability of the force measurement result. At present,many calibration methods have been proposed,but every method has its’limitations, and the accuracy of each method is different. So,the comparison of different method is needed to make a choice of which method is the best one. The normal spring constant of three kinds of commercial cantilevers are calibrated with the traceable spring constant calibration system built in our laboratory. The calibration principle is based on balance method. Then three other calibration methods (the dimensional method,the Sader method,and the thermal noise method) are used to calibrate the test cantilevers again. We compared the calibration results of different methods and discussed the advantages and shortcomings of each method in detail. The analysis results indicate that in comparison with other methods, the balance method has wider application range,higher accuracy and traceability to SI. It can become one of the best methods in calibration of the spring constant of various cantilevers accurately.%微悬臂梁探针是基于原子力显微镜(AFM)的微纳尺度力学测试中重要的力传感元件，其弹性常数的准确程度直接影响力学测量结果的可靠性。但是，目前已有的众多标定微悬臂梁探针弹性常数的方法都有各自的局限性，且准确性各异，因此需要对各种方法进行对比来选择出最佳方法。选取三种商用悬臂梁探针利用本实验室搭建的基于天平法的可溯源微悬臂梁探针弹性常数标定仪对其法向弹性常数进行标定，之后再将相同悬臂梁用三种常用标定方法（尺寸参数法，Sader法，热噪声法）进行再次标定。对不同方法测量结果进行比较，分析并详细讨论每种方法的优缺点与适用范围。结果表明相比于其他方法，微悬臂梁探针弹性常数标定仪（天平法）可测范围广，精度高，可溯源，可成为精确标定各种悬臂梁探针弹性常数的最佳方法之一。