CAPACITIVE EFFECTS ON QUANTITATIVE DOPANT PROFILING WITH SCANNED ELECTROSTATIC FORCE MICROSCOPES

A force-based scanning Kelvin probe microscope has been applied to the problem of dopant profiling in silicon. Initial data analysis assumed the detected electrostatic force couples the sample and only the tip at the end of a force sensing cantilever. Attempts to compare measurem ents quantitatively against device structures with this simple model f ailed. A significant contribution arises from the electrostatic force between the sample and the entire cantilever, which depends strongly u pon the relative size of the tip, cantilever, and lateral inhomogeneit ies in the surface topography and material composition of the sample. Actual and simulated measurements which demonstrate the characteristic signature of this effect are presented. (C) 1996 American Vacuum Soci ety.