Scanning capacitance microscopy on a 25 nm scale

A near-field capacitance microscope has been demonstrated on a 25 nm scale. A resonant circuit provides the means for sensing the capacitance variations between a sub-100-nm tip and surface with a sensitivity of 1×10 -19 F in a 1 kHz bandwidth. Feedback control is used to scan the tip at constant gap across a sample, providing a means of noncontact surface profiling. Images of conducting and nonconducting structures are presented.