We have performed scanning capacitance microscopy using a relaxation oscillator. Precision calibrations indicate a sensitivity on the order of 0.05 pF. Surface topography of metallic structures, such as machined grooves and coins, can be readily obtained either in the constant-height (non-contact) or tapping (contact) mode. Spatial resolution of sub-50 μm has been achieved.
@article{arxiv.1402.6647,
title = {Scanning capacitance microscopy using a relaxation oscillator},
author = {Marie Pahlmeyer and Andrew Hankins and Sam Tuppan and Woo-Joong Kim},
journal= {arXiv preprint arXiv:1402.6647},
year = {2015}
}