Analysis of the Influence of Electrostatic Probe on Surface Charge Measurements

Abstract

The electrostatic probe is among the most popular methods to measure the surface charge. However, the probe influences the surface charge distribution on the sample, which increases measurement error. In this paper, the electrostatic probe system is modeled to study its effect on surface charges on a circular conductor plate using electrostatic field calculation. The influence of the probe on the sample surface charges is found to increase with a decrease in the measurement distance, whereas it has a similar effect on surface charge density at different radial positions. A calibration process is proposed to measure the potential from the induced potential of the probe head. Using the measured potential, we calculate the surface charge density via the method of moments. The measurement error is analyzed when the measurement distance and number of rings are changed. The authors find that the number of rings should be appropriately reduced when the measurement distance increases to ensure the accuracy of the calculations. This research provides theoretical guidance for using the electrostatic probe and establishing a surface charge measurements system. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.