Heavy Ion Backscattering Spectrometry (HIBS) For High Sensitivity Surface Impurity Detection.

摘要

We describe a medium-energy, heavy ion beam (400 keV C(sup +)) technique for backscattering analyses of heavy trace elements on the surface of light substrates. Pulse pileup problems are eliminated by placing a thin (40 (mu)g/cm(sup 2)), self-supporting C foil in front of the surface barrier detector. In the present example the thickness is selected to range out the ions scattered from a Si substrate, while passing ions scattered from heavier impurities. Using this technique, called Heavy Ion Backscattering Spectrometry (HIBS), we show that sensitivities for impurity elements heavier than Ar on a Si substrate are as high as 10(sup 10) atoms/cm(sup 2) for Au to 5 times 10(sup 11) atoms/cm(sup 2) for Fe. 10 refs., 5 figs.