High-spatial-resolution scanning capacitance microscope using all-metal probe with quartz tuning fork

摘要

The scanning capacitance microscope (SCM) reported here uses a frequency modulation (FM) technique to control the distance between the sample and an all-metal probe. The probe was attached to a quartz tuning fork in a configuration minimizing the perturbation due to the probe. The FM-SCM yields two images of partial derivativeC/partial derivativeV and partial derivativeC/partial derivativeZ signals, where C is capacitance sensed by the probe, Z the probe-sample distance, and V a bias voltage, respectively. On a cross section of a field effect transistor, the two-dimensional p-n junction locus was observed with a spatial resolution better than 5 nm in the partial derivativeC/partial derivativeV image. The partial derivativeC/partial derivativeZ images of polysilicon gate electrodes and highly doped source/drain regions have higher contrast than the partial derivativeC/partial derivativeV images. (C) 2004 American Institute of Physics.