Correcting scanning capacitance microscope images for the effect of surface gradient

Abstract

The topological coordinate sets provided by the scanning capacitance microscope contain small distortions resulting from the finite gradient of the surface being measured. These distortions may readily be corrected provided that an expression describing them is available for the probe being used. Unlike the contacting stylus instruments, however, this correction expression is not readily derived from the probe geometry. We have studied the gradient-induced errors for a number of typical probe tip geometries and for a range of surface-to-probe separations using a large-scale mechanical model. For each of the probe tip geometries used the corrections may be adequately described in terms of the surface gradient by a simple two-parameter expression. The optimization of probe geometry for particular applications of the microscope is discussed.