Total Reflection X-ray Fluorescence (TXRF)
Total Reflection X-ray Fluorescence (TXRF) utilizes extremely low-angle X-ray excitation of a polished wafer surface to obtain the concentration of surface metallic contaminants. The incident angle of the x-ray beam (typically 0.05°) is below the critical angle for the substrate and limits excitation to the outermost surface of the sample (~ top 80Å, depending on the material). The fluorescence signal emitted from the sample is characteristic of the elemental contaminants present.
A highly surface-sensitive technique, TXRF is optimized for analyzing surface metal contamination on semiconductor wafers such as Si, SiC, GaAs or sapphire.