OXYGEN MEASUREMENTS BY ELASTIC BACKSCATTERING

The conventional Rutherford backscattering (RBS) method is often not sensitive enough for detection of oxygen when heavy elements are present. In recent years it has been found that the technique of elastic backscattering of protons and He-4 ions can provide advantages that are not attainable by RBS. The author considers the use of protons and He-4 ions in the energy regions of 1.0-4.0 MeV and 3.0-22.0 MeV, correspondingly, for oxygen profiling and lattice location in Si, YBaCuO, etc. Data on elastic scattering cross sections are reviewed. The most important characteristics of elastic backscattering such as minimum detectable concentration of oxygen, depth resolution, maximum depth of analysis are being addressed for the above-mentioned projectiles in various substrates. A comparison is made for the use of wide and narrow resonances. The problems associated with experimental data analysis are reviewed, and computer simulations including such effects as energy straggling, multiple scattering and possible Bragg rule violation are discussed. Estimations of the accuracy of elastic backscattering analysis are given. A comparison with RBS technique is made.