Analysis of electrical charging and discharging kinetics of different glasses under electron irradiation in a scanning electron microscope

Abstract

This paper presents a comparative study of electrical charging and discharging behavior of different glasses submitted to electron beam irradiation in scanning electron microscope. Charge storage and charge spreading in these glasses have been examined with help of a time resolved current method. Our interest concerns more particularly the dynamic behavior and the amount of the space charge build-up during and after electron irradiation under different experimental conditions of primary beam energy and current density. The precise contributions of different possible self regulation processes (leakage current and secondary electron emission) for charge accumulation are analyzed. Moreover, to characterize the ability of glasses to store charges in a stable way we introduce a relevant parameter that expresses quantitatively the variation in the released charge. The primary beam energy and the current density effects on the evolution of secondary electron emission yield during irradiation are also examined. As expected, the charge storage and spreading processes appear to be extremely dependent on the incident beam energy, current density and on the chemical composition of the studied glasses.