Contact stiffness calibration platform for nanomechanical property measurements with contact resonance atomic force microscopy

This paper presents a method for calibrating the contact stiffness of an atomic force microscope (AFM) cantilever tip interacting with a surface, which is a critical step in the measurement of mechanical properties at the nanometer scale. The calibration exploits the relationship between contact resonance (CR) frequency and contact stiffness during contact resonance atomic force microscopy (CR-AFM). The calibration platform introduced here consists of a series of rigid copper disks of varying diameter on top of a soft silicone substrate. Larger disks produce larger contact stiffness. We present modeling, fabrication, and characterization, and provide a first demonstration of the efficacy of this approach.