Department of Electronics Technology, Budapest University of Technology and Economics, H-1111, Budapest, Egry József street 18, Hungary.
Institute for Nuclear Research, Hungarian Academy of Sciences, H-4001, Debrecen, P.O. Box 51, Hungary.
Micron. 2019 Oct;125:102717. doi: 10.1016/j.micron.2019.102717. Epub 2019 Jul 26.
This work discusses key issues regarding the atomic force microscopy (AFM) force-curve evaluation practice, which can affect the determined Young's modulus of the investigated sample. These issues are 1) the proper calibration of lever sensitivity and the effect of its variation between the measurements; 2) the selection of proper cantilever spring constant for the investigated sample; and 3) the selection of the fitting boundaries for the contact mechanics model-based force-curve evaluation. A method is proposed, which solves the above mentioned issues, namely, categorizes the obtained force-curves based on the relation between the elastic properties of the sample and the spring constant of the cantilever, and thus helps in the selection of the proper spring constant for the given surface; helps in the identification of the optimal model-fitting boundaries, and also, provides a way of adaptive lever sensitivity calibration. The method is demonstrated on PDMS (polydimethylsiloxane) samples, which were irradiated with various fluences of ion beams to control their elastic properties in the 4 MPa - 22 GPa range. Our proposed method, if applied correctly can significantly increase the reliability of AFM force-curve evaluation.
本文讨论了原子力显微镜（AFM）力曲线评估实践中的关键问题，这些问题可能会影响所研究样品的确定杨氏模量。这些问题是：1）杠杆灵敏度的适当校准及其在测量之间变化的影响；2）为所研究的样品选择适当的悬臂梁弹簧常数；以及 3）基于接触力学模型的力曲线评估的拟合边界的选择。提出了一种解决上述问题的方法，即根据样品的弹性性质和悬臂梁的弹簧常数之间的关系对所获得的力曲线进行分类，从而有助于为给定表面选择适当的弹簧常数；有助于识别最佳模型拟合边界，并且还提供了一种自适应杠杆灵敏度校准的方法。该方法在 PDMS（聚二甲基硅氧烷）样品上进行了验证，这些样品经过不同剂量的离子束辐照，以控制其在 4 MPa-22 GPa 范围内的弹性性质。如果正确应用，我们提出的方法可以显著提高 AFM 力曲线评估的可靠性。
