Surface chemical analysis: Comparing and exchanging data

Abstract

The current status of repeatability and reproducibility in interlaboratory studies in surface analysis using Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), dynamic and static secondary ion mass spectrometries (SIMS), and sputtering are briefly reviewed. Repeatabilities are governed by the quality of the instrument design and the procedure for instrument use. Reproducibility from laboratory to laboratory requires the use of transfer standards which may be technique wide, as in the cases of AES and XPS, or sample specific as in the case of dynamic SIMS. Repeatabilities of intensity ratios with good instruments and procedures should be better than 2% for all techniques for suitable samples. Repeatabilities of the energy scale in good electron spectrometers average around 0.025 eV. The reproducibilities in quantification have improved to around 10% relative standard deviation. The measurement infrastructure is developing well and it needs to be reinforced by the relevant documentary standards to enable analysts to transfer and exchange data, at the above levels, and to improve it where necessary. The analyst needs methods of validating both equipment and software and the laboratory management, in turn, needs methods of testing the analyst’s proficiency. These aspects need development of appropriate documentary standards, as pioneered by ASTM Committee E-42 on Surface Analysis and, at an international level, by the International Standards Organization Technical Committee 201 on Surface Chemical Analysis.