Comparison of scanning capacitance microscopy measurements in open and closed loop modes on highly doped silicon monolayers

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.