HYDROGEN ANALYSIS BY SECONDARY ION MASS-SPECTROMETRY USING HCS+ IONS

HCs+ secondary ions produced under Cs+ primary ion bombardment have been utilized for the analysis of hydrogen in thin solid films by secondary ion mass spectrometry. Detection limits presently achievable are on the order of some 10(19) H-atoms/cm3 at modest sputter erosion rates of less-than-or-similar-to 1 nm/s. In a series of hydrogenated amorphous Si thin film specimens, the HCs+ intensities are found to scale linearly with the H-content, providing thus the possibility of a quantitative evaluation of the hydrogen concentration by means of a single relative sensitivity factor. For those samples a depth resolution of about 10 nm is demonstrated for layers with a thickness of up to 1-mu-m. Using a focused primary beam and detecting HCs+ secondary ions, elemental distributions of hydrogen with a lateral resolution of about 5-mu-m have been recorded. The energy spectrum of HCs+ is found to exhibit a close similarity with those of SiCs+ and Cs+ ions.