分析電子顕微鏡における試料汚染の改善

Abstract

This paper describes the method to measure quantitatively the contamination caused by the use of a micro electron probe, and instrumental improvements for reducing it. These improvements include the adoption of a new type of vacuum grease and the development of a new type anti-contamination device. Since the weight of contamination deposits changes lineally with the probe irradiation time, a highly accurate method of contamination measurement has been established by indicating the contamination rate in g/min. Thus, it has become possible to correctly evaluate instrumental improvements for reducing contamination. The partial pressure of hydrocarbon gases in the specimen chamber was reduced by approx. one order, through various instrumental improvements. This resulted in a drastic reduction of the contamination rate and therefore in the performance improvement of the analytical electron microscope. In this experiment, any specimen pre-treatment that eliminates contamination source existing in a specimen itself, was not carried out. But it is now important to establish such a treatment in order to further reduce the contamination.