ISS imaging and depth−profile analysis using beam rastering and signal gating

Ion scattering spectrometry (ISS) has been shown to be a valuable technique for the chemical analysis of surfaces. As the ion beam (energy less than 3 keV) is sputtering the surface, a depth profile is obtained by sequential measurement of the scattered ion energy distribution. However, when a stationary ion beam is used, the true−depth distribution of elements may be distorted due to crater−edge effects. This difficulty has been overcome by rastering the ion beam over the sample, and gating the analyzer signal so that only the flat−bottomed center of the crater is analyzed.In addition, the scattered ion signal has been used to image the lateral distribution of the surface elemental composition.