Device and method for measuring surface charge distribution

A device for measuring the surface charge distribution of a sample, comprising:

• an electric charger configured to irradiate a sample with a charged particle beam;
• a detector configured to detect a boundary between an area in which the charged particle beam is inverted before reaching the sample and an area in which the charged particle beam reaches the sample;
• a first measuring element configured to measure a value of potential at a potential saddle point formed above the sample;
• a selector configured to select one structure model from preset multiple structure models and select a tentative space charge distribution associated with the one structure model;
• a first calculator configured to calculate a space potential at the potential saddle point by electromagnetic field analysis using the selected structure model and tentative space charge distribution;
• a determiner configured to compare the calculated space potential and the measured value and determine the tentative space charge distribution as a space charge distribution of the sample when an error between the space potential and the measured value is within a predetermined range;
• and
• a second calculator configured to calculate a surface charge distribution of the sample by electromagnetic field analysis based on the determined space charge distribution of the sample.