Material analysis using combined elastic recoil detection and Rutherford/enhanced Rutherford backscattering spectrometry

Abstract

Three complimentary ion beam techniques will be combined in the analysis of oxide and nitride based materials, in particular BN SiC and La 0.85Sr 0.15CoO 3. These materials can be synthesized over composition ranges which vary the physical and electrical properties, and therefore an accurate measure of the composition profiles is critical for controlling these properties. Elastic recoil detection (ERD) revealed the composition of light elements from H to O, and Rutherford backscattering spectrometry (RBS) gave the composition of heavier elements (e.g., Si, Sr, Co and La). Enhanced Rutherford backscattering spectrometry (ERBS) complimented these techniques by utilizing enhanced cross sections, greater than Rutherford, to increase the signal-to-noise ratio for analysis of mid-range elements O, C, and N. ERD with 24 MeV Si ions gave profiles for H, B, and N in thin films, and 30 MeV Si was able to profile O in the top portion of heavier samples. Although 2.8 MeV He RBS worked well for heavier elements, ERBS utilized He ions at 3.5 MeV for N analysis and 8.7 MeV for O analysis, because at these energies the cross sections are 2 and 22 times Rutherford, respectively. Also, the depth of analysis was greater with ERBS because of the increased incident energy.