Analysis of solid surfaces by Neutral Beam Incidence Ion Scattering Spectroscopy.

Abstract

Low-energy rare-gas Ion Scattering Spectroscopy (ISS) has been improved by the use of neutral beams as projectiles, which we call Neutral Beam Incidence Ion Scattering Spectroscopy (NBISS).Experiments on ISS and NBISS are compared on the basis of electron exchange between the projectiles and solid surfaces.In ISS, the scattered ions consist of two elements: One is “surviving ions” characterized by the ions which survived neutralization, and the other is “reionized ions” characterized by those which experienced neutralization on the incoming trajectory and subsequent reionization during the violent collision. The shadowing and focusing effects are often weakened in the intensity of surviving ions, whereas these effects appear intensively in the intensity of reionized ions. Since the threshold energy for the reionization is different for the combination of projectiles and targets, these effects are often not observed at all in the ISS spectra. On the other hand, these effects appear explicitly in the NBISS spectra. It is also found that NBISS is valid for analyzing insulator surfaces since charging effects are minimized by the use of neutral beams.