Surface analysis for Si-wafers using total reflection X-ray fluorescence analysis

Summary

Total Reflection X-Ray Fluorescence Analysis is presented as a novel analytical tool for the determination of metal impurities on Si-Wafer surfaces [1]. This method allows accurate quantification of surface coverages down to 10¹¹ atoms/cm² in a non-destructive way. The technique uses a molybdenum tube, a Si(Li) detector, and instrumentation for the exact control of the angle of incidence which must be set to a particular value below the cricitical angle for total reflection with an accuracy better than 0.1 mrad. Advantages are the lack of sample preparation and vacuum. Standards for quantification can be easily produced. Repeatability tests on three different wafers show good variability even for low concentrations.