Elastic Backscattering of Ions for Compositional Analysis

Abstract

BS (elastic backscattering spectrometry, either RBS or EBS) using MeV beams is used to obtain elemental depth profiles of thin films up to ∼10 mm thick. Depth resolution degrades with depth but can be ∼1 nm at the surface. Various ion beams and various beam energies can be selected to obtain the optimal analytical conditions for particular samples. We will briefly mention the use of microbeams since many samples are small or laterally non‐homogeneous. We will also briefly mention the use of ion channelling geometries for characterizing defects in single crystal samples. We should also mention that LEIS and MEIS are both RBS techniques, but they use low energy beams and will not be covered in this article. We treat all the IBA techniques synergistically. The present article considers the details of analysis using a particle detector placed in the backscattering direction. We explicitly distinguish between RBS and EBS, even though in any particular BS spectrum there may be (and often are) both RBS and EBS signals, since there is a philosophical difference of treatment between a signal resulting from a Coulomb interaction and one resulting from an interaction that must be treated quantum mechanically.

Nanoscale Control of Structure and Composition for Nanocrystalline Fe Thin Films Grown by Oblique Angle RF Sputtering

“…In ion beam analyses, the areal density or thin film units (TFU) are used, since the energy loss is measured in eV/(atoms/cm 2 ), with one monolayer typically containing in the order of 10 15 atoms/cm 2 [ 54 ]. Therefore, the depth scale is given in TFU units [ 55 ], where 1 TFU = 10 15 atoms/cm 2 . In order to profile the film thicknesses, two energies were used for measuring the oxygen composition (3.043 MeV and 3.075 MeV).…”

Films Deposited from Reactive Sputtering of Aluminum Acetylacetonate Under Low Energy Ion Bombardment

“…For each one of the EDS analysis, the beam penetration depth was simulated by the Monte Carlo Simulation of Electron Trajectory in Solids -CASINO software 18 . The elemental composition of the film prepared with no bias was determined using energy recoil detection (ERD) analysis for hydrogen 19 content evaluation and elastic backscattering spectroscopy (EBS) 19 for heavier elements determination (C, O, Al and Fe). The first experiment was performed using a 2.2 MeV helium beam with the detector placed at a scattering angle of 20º with respect to the beam direction.…”