High-energy elastic backscattering of helium ions for compositional analysis of high-temperature superconductor thin films

Abstract

A thin-film technique for measuring the chemical composition of Y-Ba-Cu-O thin films to a few percent accuracy is described. This technique utilizes non-Rutherford backscattering of 8.8 MeV helium ions, which has an increased sensitivity 16O by a factor of 25 over Rutherford backscattering spectrometry. The ratios of the cross sections for He++ scattered from oxygen, copper, and yttrium relative to barium are easily determined using thin-film standards that can be fabricated in any deposition system capable of producing thin-film superconductors. The technique does not require the constant use of standards or accurate charge determination.