Quantitative depth profiling of light elements by means of the ERD E × B technique

Abstract ERDA [J. L'Ecuyer et al., J. Appl. Phys. 47 (1976) 381] is a technique of great interest for quantitative depth profiling of light elements in matter. The use of crossed electric and magnetic fields ( E × B filter) [G.G. Ross et al. J. Nucl. Mater. 128/129 (1992) 484; G.G. Ross and L. Leblanc, Nucl. Instr. and Meth. B 62 (1992) 484] in place of the traditional absorber, enhances the resolution by eliminating the straggling induced normally by the absorber and removes the uncertainty on the absorber thickness. The E × B filter allows the simultaneous detection of different particles such as H, D and He. This work presents the first ERD E × B depth profiling by means of a heavy ion beam. Compared with the usual ERD E × B with 350 keV He, the 2.54 MeV 15 N beam enhances scattering cross section by a factor of 3, has equivalent depth resolution (1–3 nm at surface) and gives a depth probe twice deeper. However, 15 N ions sometimes induce high desorption compared to He. H, D and He were implanted in Be and Si at energies from 800 eV to 10 keV. The experimental depth distributions are compared with those obtained by TRIM95 [J.F. Ziegler and J.P. Biersack, The Stopping and Range of Ions in Solids (Pergamon, New York, 1995)] and by other experimental techniques. Reproducibility is very good between the different results obtained experimentally. Profile modification induced by the ion beam is also shown.