Calibration standard prodn. for X=ray fluorescence analysis of solids - by dripping plastics dispersion containing impurity atoms on to rotating substrate and then hardening film

摘要

The calibration standard for the X-ray fluorescence analysis of solids, esp. semiconductors, is based on the provision of an extremely thin plastics film contg. an appropriate concentration of impurities, which is deposited on the the surface of the sample of semiconductor under investigation. The impurities can be deposited by prepg. an aq. soln. or plastic dispersion such as acrylic ester, polyvinylacetate etc. contg. the impurity atoms. The semiconductor substrate is attached to a centrifuge table and rotated at speeds up to 4000 rev/min. The plastics dispersion with impurities is then dripped onto the substrate so that a uniform coating is applied. The film is then dried and hardened. The doping concentration can be calculated from the plastic film weight per unit area multiplied by impurity atom weight per plastic film weight unit.