A mechanism of ion production in secondary ion mass spectrometry

Abstract

A mechanism of ion production from sub-monolayers of organics adsorbed on a surface is proposed. This mechanism is used to explain why preformed ions are observed with greater abundance than other types of secondary ions in secondary ion mass spectrometry (SIMS). Primarily, the production of positively charged ions is emphasized, but the mechanisms proposed are just as applicable to negatively charged ions. From an understanding of these mechanisms, one can optimize the production of ions and thereby increase the sensitivity of the SIMS analysis.