CHARGING AND CHARGE COMPENSATION IN AES ANALYSIS OF INSULATORS

Practical AES analysis of insulating ceramic materials is often impeded by charging of the surface. After an outline of the basic principles of charging and its effect on qualitative and quantitative AES, generally applicable methods for charge compensation are described, such as reducing the primary current density, minimizing the absorbed current path, and increasing the total secondary electron emission. Reduction of charging by generation of a positive surface charge using additional low energy ion and/or electron irradiation as well as deposition of a small amount of metal on the surface are discussed. Furthermore, the effects of electron beam-induced desorption, its compensation in sputter profiling and of beam heating are estimated with respect to quantitative AES of ceramics.