Determination of the electron beam irradiated area by using a new procedure deriving from the electron beam lithography technique

Abstract

The study of the charge trapping properties in non-conductive solids by means of a Scanning Electron Microscope requires the knowledge of both the injected charge and the current densities over the irradiated sample area. The aim of this paper is to set-up an experimental technique leading to a more accurate determination of this area. After investigation of the parameters which influence the determination of the irradiated area size by using the electron beam lithography technique (electron beam energy, resist thickness and nature of the substrate), we describe a new experimental procedure derived from this technique. In this procedure, we replace the usual resist develop process by a direct SEM resist surface imaging immediately after the irradiation step. Thus, we find that the irradiation area on insulating glass substrate is considerably wider than that on conducting copper substrate. Moreover, a SEM contrast inversion is observed. These different behaviours are interpreted by considering the charging ability of glass and the conductivity nature of copper.