Grutzik Scott J, Gates Richard S, Gerbig Yvonne B, Smith Douglas T, Cook Robert F, Zehnder Alan T
Field of Theoretical and Applied Mechanics, Cornell University, Ithaca, New York 14853, USA.
Rev Sci Instrum. 2013 Nov;84(11):113706. doi: 10.1063/1.4832978.
There are many atomic force microscopy (AFM) applications that rely on quantifying the force between the AFM cantilever tip and the sample. The AFM does not explicitly measure force, however, so in such cases knowledge of the cantilever stiffness is required. In most cases, the forces of interest are very small, thus compliant cantilevers are used. A number of methods have been developed that are well suited to measuring low stiffness values. However, in some cases a cantilever with much greater stiffness is required. Thus, a direct, traceable method for calibrating very stiff (approximately 200 N/m) cantilevers is presented here. The method uses an instrumented and calibrated nanoindenter to determine the stiffness of a reference cantilever. This reference cantilever is then used to measure the stiffness of a number of AFM test cantilevers. This method is shown to have much smaller uncertainty than previously proposed methods. An example application to fracture testing of nanoscale silicon beam specimens is included.
有许多原子力显微镜（AFM）应用依赖于量化AFM悬臂尖端与样品之间的力。然而，AFM并不会直接测量力，因此在这种情况下需要知道悬臂的刚度。在大多数情况下，感兴趣的力非常小，所以使用的是柔性悬臂。已经开发出了许多非常适合测量低刚度值的方法。然而，在某些情况下，需要刚度大得多的悬臂。因此，本文提出了一种直接、可溯源的方法来校准非常硬（约200 N/m）的悬臂。该方法使用一台配备仪器并经过校准的纳米压痕仪来确定参考悬臂的刚度。然后用这个参考悬臂来测量多个AFM测试悬臂的刚度。结果表明，该方法的不确定度比以前提出的方法小得多。文中还包括了一个纳米级硅梁试样断裂测试的应用实例。
