Tip-to-Sample Distance Dependence of dC/dZ Imaging in Thin Dielectric Film Measurement

Abstract

We have developed scanning capacitance microscopy (SCM) with a self-sensing conductive probe that can be used to obtain static capacitance (dC=dZ) images by virtue of the vertical vibration of the probe tip. This technique for dC=dZ imaging can delineate features, such as thickness variations or fixed charge distributions, within a dielectric film and provide a lateral resolution comparable to that of simultaneously obtained topography images. In this work, we have experimentally revealed that the lateral resolution of a dC=dZ image is insensitive to the probe tip amplitude, and the sensitivity of dC=dZ images strongly depends on the distance of the gap between the probe tip and the sample surface. These results and the force-distance characteristics of the self-sensing conductive probe indicate that the dC=dZ signal is mostly determined by the probe tipsample capacitance and also that the spatial resolution of dC=dZ imaging is not affected by the surface-adsorbed meniscus layer under a vacuum environment measurement. Finally, we have demonstrated sub-10-nm spatial resoluton in dC=dZ imaging for thin dielectric film measurement.

Study of the Electronic Structure of Individual Free-Standing Germanium Nanodots Using Spectroscopic Scanning Capacitance Microscopy

“…However scanning capacitance microscopy (SCM), a promising nano-characterization metrology technique with spatial resolution of the order of 10 nm, [13][14][15] utilizing a platinum probe tip with a small radius of curvature (typically 20 nm or smaller), the SCM spectroscopic technique is able to directly investigate the local electronic structure of a single Ge nanodot. This would enable the properties due to the specific nanodot to be differentiated from the properties of the nanodot ensemble, thus providing a more accurate assessment of the characteristics electronic structure associated with an individual Ge nanodot.…”