Kelvin Probe Force Microscopy: Measurement Data Reconstruction

摘要

The Kelvin Probe Force Microscopy (KPFM) is a method to detect the surface potential of micro- and nanos-tructured samples using a common Scanning Probe Microscope (SPM). The electrostatic force has a very long range compared to other surface forces. By using SPM systems the KPFM measurements are performed in the noncontact region at surface distances greater than 10nm. In contrast to topography measurement, the measured data is blurred. The KPFM signal can be described as a convolution of an effective surface potential and a microscope intrinsic point spread function, which allows the restoration of the measured data by deconvolution. This paper deals with methods to deconvolute the measured KPFM data with the objective to increase the lateral resolution. An analytical and a practical way of obtaining the point spread function of the microscope was compared. In contrast to other papers a modern DoF-restricted deconvolution algorithm is applied to the measured data. The new method was demonstrated on a nanoscale test stripe pattern for lateral resolution and calibration of length scales (BAM-L200) made by German Federal Istitute for Materials Research and Testing.