Relative positive-ion yields from transition-metal oxide systems under dynamic secondary ion mass spectrometry conditions

Abstract

In this work, first-row transition-metal oxides and several series of mixed first-row transition-metal oxides have been examined under dynamic SIMS conditions.

For studies on the mixed oxides, relative sensitivity factors have been derived for a given type of mixed oxide from positive SIMS spectra, which can be used to quantitatively analyse other mixed oxides of that type.

In addition, an investigation was made to determine the factors which control relative ion intensities observed in positive SIMS spectra recorded for mixed transition-metal oxides. Attempts to correlate experimental relative ion intensities with solid-state properties such as bulk composition, lattice parameter or metal–oxygen bond strength in the solid met with limited success. However, evidence was obtained for the observed relative ion intensities being controlled by the relative stability of the ions produced in the vapour phase above the solid. Relative ion and neutral partial pressures in the plasma above the sputtered region of a solid appear to be controlled by ion–molecule equilibria.