Scanning capacitance microscopy (SCM) measurements have been performed on highly doped Si monolayers both in constant-dV and constant-dC modes. The performances of these operating modes have been compared in terms of both signal sensitivity to high doping levels and spatial resolution. A higher sensitivity to boron-doped Si monolayers separated by 30 nm in constant-dC mode is observed. This result is attributed to a higher intrinsic spatial resolution for this latter mode and suggests the further ability of the constant-dC mode to deconvolute the SCM signal to carrier distribution near highly doped layers. (c) 2006 Elsevier Ltd. All rights reserved.