Article dans une revue avec comité de lecture


Second crossover energy of insulating materials using stationary electron beam under normal incidence
Nuc. Instr. Meth. Phys. Res. B 266 719 (2008).

par   E.I. Rau , Slim FAKHFAKH , M.V. Andrianov , E.N. Evstafeva , Omar JBARA , Sébastien RONDOT , Dominique MOUZE

Résumé :

Abstract

The purpose of this paper is to give some aspects of charging effects on dielec. materials submitted to continuous electron beam irradn. in a scanning electron microscope (SEM). When the dielec. is irradiated continuously, the so-called total yield approach (TYA) used to predict the sign of the charge appeared on electron irradiated insulators fails because the charge accumulated in the dielec. interferes with the electrons emission processes. Based on previous exptl. and theor. works found in the literature, an anal. of the evolution of the electron yield curves ? = f(E 0) of insulators during irradn. is given. The aim of this work is firstly to det. exptl. the second crossover energy E 2C under continuous electron irradn. (charging conditions) and secondly to demonstrate that the charge balance occurs at this beam energy and not at E 2 the energy deduced from non-charging conditions (pulse primary electron beam expts.) as commonly asserted. It is however possible to apply the TYA by substituting the crit. energy E 2 for E 2C. The exptl. procedure is based on simultaneous time dependent measurements of surface potential, leakage current and displacement current. The study underlines the difference between the landing energy of primary electrons E L at the steady state and the second crossover energy, E 2C, for charged samples. Some preliminary results are also obtained concerning the influence of the incident beam d. on the energy E 2C. The samples used for this study are PMMA, polycryst. silicone dioxide (p-SiO2), polycryst. alumina (p-Al2O3) and soda lime glass (SLG).