Application of Instantaneous Cantilever Frequency Fluctuation in Atomic Force Microscope Control Loop

Atomic Force Microscopy (AFM) systems are used for scanning samples at the nano-meter size, including semiconductor products, biological cellular compounds and many others. AFM systems generally probes the height of its sample surface profile, through the van der Waals force interaction between the probe and sample, where the sensitivity of AFM systems are at the pico-Newton range. In this paper, a full cantilever/probe model is simulated in order to find the instantaneous frequency response of the tapping mode AFM cantilever beam through Hilbert-Huang Transform (HHT), with Empirical Mode Decomposition (EMD). The resultant Intrinsic Mode Functions (IMF) derivation showed frequency shifting higher when the cantilever is held at a smaller gap between the sample. This shows a vast potential to monitor the frequency of AFM system for further use to increase operational mode and speed for the system.