Depth profiling of light elements in materials with high‐energy ion beams

The detection and depth profiling of light impurity elements near the surface of solids pose special difficulties of signal/background ratio and kinematics. We review some methods of getting around these problems. We limit ourselves to methods which (1) are nondestructive because they use the inelastic energy loss of charged particles traversing matter to gain depth information, rather than erosion of the sample, and (2) have wide applicability because they use elastic scattering rather than an isotope‐specific nuclear reactions. Generally, the signal/background problem is alleviated by using an interaction process whose cross section does not increase rapidly (or not at all) with the A or Z of the target atoms. The kinematical problem—which often compounds the signal/background difficulty—is avoided by using a beam of different mass than usual, a different counting geometry than the usual backscattering, and/or thin foils for the samples. We describe in more detail the method of elastic recoil detection ...