NOVEL DETECTION SCHEME FOR THE ANALYSIS OF HYDROGEN AND HELIUM BY SECONDARY ION MASS-SPECTROMETRY

For the analysis of hydrogen and helium in solids and thin films by secondary ion mass spectrometry, the use of Cs+ primary ions in conjunction with the detection of HCs+ and HeCs+ molecular ions is proposed. For both species, detection limits of the order of 10(19) atoms cm-3 are obtained at sputter removal rates of approximately 1 nm s-1. A relative depth resolution of approximately 2% is demonstrated for hydrogenated amorphous Si layers on single-crystal Si. In these specimens, the HCs+ intensities scale linearly with the hydrogen concentrations c(H) in the range investigated (c(H) < 20 at. %); hence, a quantitative evaluation of the H content appears possible by means of a single standard.