Nano C-V imaging of Semiconductor Devices with Scanning Microwave Impedance Microscopy

Abstract

Two doped semiconductor samples are measured using probe-based Scanning Microwave Impedance Microscopy (sMIM). One is a plan-view polished CMOS image sensor and the other is a cross-section polished power device. Both samples are imaged with sMIM using two different approaches: the first using a dual pass method with dC/dV images acquired simultaneously with sMIM during the first pass in contact mode, and the second pass at a fixed offset from the surface. The second method uses a non-resonant mode where C- V are acquired at specific lateral locations. The C- V curves are used to determine polarity compared to dC/dV and also to distinguish p-n junctions, characterize doping concentration, and build images at constant DC values to discern subtle changes not evident in traditional SCM imaging.