Deuterium depth profiling in polymers using heavy ion elastic recoil detection

We have used Ne-20 and Ar-40 beams with energies between 3 and 8 MeV for elastic recoil detection (ERD) analysis of hydrogen isotopes in polymer samples and have also studied the depth resolution and the radiation damage. For the investigation of polymer mixtures it was possible to improve the depth resolution of ERD down to 8 nm FWHM without changing the experimental setup of conventional ERD, due to the higher energy lass factor of heavier ions and a reduced stopper foil thickness. For an improved surface depth resolution heavier ions are suitable, whereas lighter elements have a larger profiling depth. We found a Ne-20 beam with an energy between 3 and 6 MeV to have a maximum analysing depth of 380 nm with a near surface depth resolution of 9 nm; however, for high resolution Ar-40-ERD measurements this maximum profiling depth is reduced to 90 nm, Due to the larger Rutherford scattering cross-section of heavier ions the measuring time decreases with increasing ion mass, We have investigated the ion beam radiation damage in polymer samples and introduced beam current density limits related to polystyrene samples. These results are supported by model calculations which give approximated values of the radiation damage, (C) 1998 Elsevier Science B.V.