Investigation of capacitive coupling voltage contrast using a specimen charging model

Abstract

The capacitive coupling voltage contrast effect has been simulated using a versatile charge simulation program. Simulation shows that the potential distribution of the irradiated passivation surface depends on the size and the shape of the beam profile. When the width of the beam spot is equal to or less than the width of the buried electrode and the electrode voltage is positive, a negative charge ring is formed around the irradiated spot. As a result of this charge ring, the irradiated spot above an electrode with non-positive voltage need not charge to a positive equilibrium potential. Differential charging of passivation surface enhances the lateral field on the surface. The field is highest during voltage switching, its amplitude depends on the voltage swing on the electrode and can be several times stronger than the field existing on the uncharged surface. The field strength reduces slightly at equilibrium. © 1994.