Investigation of insulator electron beam charging effects and related breakdown phenomena

Insulators are charged under electron bombardment and the variation of potential V is measured as a function of the electron dose D. Three cases are observed: (1) V is proportional to D; (2) V reaches a plateau; and (3) the V(D) curve shows various extrema. These are respectively interpreted as: (1) due to a stable implanted charge in the electron voltage range used to charge the sample; (2) due to the appearance of a steady-state leakage current occuring when a critical space charge is reached; and (3) due to structural modifications of the material. These interpretations are supported by electrostatic calculations combined with electron microscopy experiments.<>