A novel CMA alignment technique for Auger spectroscopy

Abstract

Quantitative analysis using Auger electron spectroscopy has not yet achieved the degree of accuracy and precision that other spectroscopies (e.g., electron microprobe, etc.) have developed. This can be partially attributed to the basic data collection procedures used for sample positioning and calibration, and the lack of quantitative correction procedures relating the non-linearities observed between the signal intensity and the concentration for a multielement sample. This work deals with a novel technique used to spectroscopically align the intensity and shape of the Auger spectrum and calibrate the energy axis of the CMA (cylindrical mirror analyzer) which leads to an improvement in accuracy and precision. It is equally valid for either off-axis or co-axial electron gun/CMA geometry. The alignment technique is based upon reproducing the standard and unknown sample position mechanically, rather than spectroscopically, by using a eucentric, externally adjustable tilt axis stage after an initial alignment procedure is completed. Energy calibration is accomplished on a calibration standard by referencing a known Auger transition. Data are presented illustrating the effect of CMA focal point position on energy and intensity calibration. Using this technique, which is considerably faster than a previous technique employed it is possible to achieve 1 eV energy accuracy and a few percent intensity reproducibly.