Results of a joint auger/esca round robin sponsored by astm committee E-42 on surface analysis. Part II. Auger results

Abstract

We report the results of a round robin involving kinetic-energy (KE) and relative-intensity measurements on high-purity samples of copper and gold by Auger-electron spectroscopy. These results were obtained using 28 different instruments or analyzers manufactured by four companies. We found that the spread in reported KE values ranged from 7 eV at a KE of 60 eV to 32 eV at a KE of ∼2025 eV. The total spread in reported intensity ratios ranged from a factor of ∼38 for the ∼6O eV and ∼92O eV peaks of Cu to a factor of ~̊120 for the ∼70 eV and ∼2025 eV peaks of Au. We have analyzed the observed trends in some detail. The systematic error of kinetic-energy measurements increases with kinetic energy for many instruments. Even though all instruments were adjusted with the use of 2 keV elastically scattered electrons, the spread in the reported positions of the ∼2025 eV Au peak indicates that the instruments were not adequately calibrated. Examples of erratic response were found in the measurements of relative intensities; it was believed, though not proved, that the more extreme values of intensity ratios were associated with instrumental malfunctions or operator mistakes. As in the similar ESCA round robin (Part I), the spread in reported Auger kinetic energies and relative intensities demonstrates clearly the need for standards (e.g., calibration methods, operating procedures, and data analysis) to ensure that data of known accuracy can be obtained routinely. Until suitable standards are available, interested individuals may find it useful to compare measurements using their own Auger or ESCA instruments with the group results and the trends found in the round-robin results.