Hydrogen depth resolution in multilayer metal structures, comparison of elastic recoil detection and resonant nuclear reaction method

Four different metals: Al, Cu, Ag and An have been used to produce four special multilayer samples to study the depth resolution of hydrogen. The layer structure of each sample was analysed using 2 MeV He Rutherford backscattering spectrometry, 4.5 MeV He elastic recoil detection (ERD) and 30 MeV F6+ HIERD. Moreover the hydrogen distribution was analysed in all samples using H(N-15, alphagamma)C-12 nuclear reaction analysis (NRA) with resonance at 6.385 MeV. The results show that the best depth resolution and sensitivity for hydrogen detection are offered by resonance NRA. The He ERD shows good depth resolution only for the near surface hydrogen. In this technique the depth resolution is rapidly reduced with depth due to multiple scattering effects. The 30 MeV F6+ HIERD demonstrated similar hydrogen depth resolution to He ERD for low mass metals and HIERD resolution is substantially better for heavy metals and deep layers. (C) 2002 Elsevier Science B.V. All rights reserved.