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Total Reflection X-ray Fluorescence

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 0.05-0.5°) is below the critical angle for the substrate and limits excitation to the outermost surface of the sample (~ top 80 Å, depending on the material). The fluorescence signal emitted from the sample is characteristic of the elemental contaminants present.

Surface Sensitivity

The surface sensitivity of TOF-SIMS makes it a good first pass at problem solving to give an overview of what types of species are present on a sample. Other techniques can then be used to obtain additional information. TOF-SIMS is also a technique that can detect species at significantly lower levels than traditional surface analysis techniques such as XPS and Auger.


A highly surface-sensitive technique, TXRF is optimized for analyzing surface metal contamination on semiconductor wafers such as Si, SiC, GaAs or sapphire.

Ideal Uses of Total Reflection X-ray Fluorescence

  • Metallic surface contamination on semiconductor wafers


  • Trace element analysis
  • Survey analysis
  • Quantitative
  • Non-destructive
  • Automated analysis
  • Whole wafer analysis (up to 300 mm)
  • Can analyze many substrates, e.g. Si, SiC, GaAs, InP, sapphire, glass


  • Cannot detect low-Z elements (below Na on periodic chart)
  • Polished surface required for best detection limits

TXRF Technical Specifications

  • Signal Detected: Fluorescent x-rays from wafer surface
  • Elements Detected: Na-U
  • Detection Limits: 109 – 1012 at/cm2
  • Depth Resolution: 30 – 80 Å (Sampling Depth)
  • Imaging/Mapping: Optional
  • Lateral Resolution/Probe Size: ~10 mm

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