Accuracy Improvement of Vertical Defect Characterization Using Electrostatics

This study led to the proposal of a new numerical scheme for nondestructive evaluation using electrostatics. A system of equations was constructed to describe the relationship between the charge density on the defect and the electrostatic field observed in space. The coefficient matrix of the simultaneous equations was derived using the Fredholm integral equation of the first kind. This ill-posed problem was solved using the Tikhonov regularization method. The proposed method uses a matrix that reflects the decay effect of the electric field for the regularization term. The accuracy of the proposed method was verified through numerical experiments in which the observed electric field was derived using forward analysis computation. A formula was defined to quantitatively evaluate the error. Our results confirmed that the proposed method provides solutions that are more accurate than the standard Tikhonov regularization.