Tip-shape effects on electrostatic force microscopy resolution

A detailed analysis of electrostatic interactions between a dc-biased tip and a metallic or insulating sample is presented. For inhomogeneous thin dielectric films, the scanning probe signal is shown to be proportional to the convolution between an effective surface profile and a response function of the microscope. Based on the properties of the response function, tip-shape effects on the lateral resolution in electrostatic force microscopy are discussed. For tip-sample distances D smaller than the tip radius R, the resolution is found to be proportional to rootDR.