Quantification of scanning capacitance microscopy measurements for 2D dopant profiling

Several Scanning Probe Microscopy (SPM) techniques are currently under development for 2D dopant profiling; among these the Scanning Capacitance Microscopy (SCM). The signal-to-noise. ratio in SCM measurements is a critical issue, due to the small tip-to-semiconductor differential capacitance (typically in the attoFarad range). Many factors may have a negative influence on the reproducibility of SCM data and must be kept under control: sample-related problems, tip-related problems, and problems related to the electrical operating conditions. Furthermore, the conversion of the SCM experimental data into a quantitative 2D map of the local dopant concentration requires a huge effort in terms of reverse simulation. In this paper, the current procedures for preparing SCM samples are briefly reviewed. Then, the sample preparation and the experimental dC/dV curve of a calibrated staircase structure are presented. Finally, the experimental SCM data (the dC/dV and the conversion curves) are compared with the theoretical data simulated with a device simulator. (C) 2000 Elsevier; Science Ltd. All rights reserved.