Electron beam effects during analysis of glass thin films with auger electron spectroscopy

Abstract

Migration of sodium in thin films of soda-silica glass deposited on a stainless steel substrate has been studied. The amounts of charge trapping and local heating were a strong function of beam parameters for thin films. For example, the time required for the sodium Auger signal to decay to 50% of its initial value increased as the beam energy was increased or as the current density was decreased. The rearrangement of sodium due to charge trapping was calculated and compared to experimental data. The calculated and experimental data agree well and indicate that fields of -lo5 V cm-' exist during analysis. The depth distribution of sodium indicates that either electrons or ion bombardment can cause sodium migration during analysis. The cross-section for electroninduced desorption was measured to be 3 X lo-'' cm2 for sodium in this glass, therefore it is only important at very high current densities.

Electron beam dissociation of CO and CO2 on ZnS thin films

“…There are many reports of electron stimulated reactions on solid surfaces, with the most common being either electron stimulated desorption, [36][37][38][39] stimulated adsorption, 40,41 oxidation, 42 or molecular dissociation [43][44][45] of gases. This indicates that an electron stimulated surface reaction is taking place when the C and/or O peaks increase and the S decreases in the presence of an electron beam.…”

Approaches to analyzing insulators with Auger electron spectroscopy: Update and overview

“…It has long been recognized that enabling the incident electron beam to penetrate a thin insulating film on a conducting substrate can reduce or eliminate charge build-up [5,25,26]. The critical condition occurs when the penetration depth of the incident electrons exceeds the thickness of the insulating layer.…”

“…While measurements of depth profiles for "bulk" insulating materials can be challenging, sputter profiles can often be measured of thin insulating films on conducting substrates (e.g., corrosion layers) and sometimes benefit from the increased primary-energy approach described earlier [26]. Covering an insulator surface with a metal coating before sputtering might be considered a special case of the aperture or mask approach described earlier, but has proved useful in some circumstances [31].…”

“…In spite of possible charging and damage complications, researchers routinely have been able to collect informative AES profiles of glasses and other insulators. It has also been possible to study the extent to which the primary beam induces elemental migration [26,59].…”

“…Such samples are common in the electronics and sensor industries. In these cases, it is often useful to use an electron-beam energy high enough so that the beam penetrates the insulating layer to create a conduction pathway that minimizes charging [5,26] as shown in Figure 7.…”