Mechanisms of atomic ion emission during sputtering

Abstract

Several major experimental and theoretical findings made in the last few years on the mechanisms of secondary ion emission are summarized. There is a strong indication that the phenomena can be divided into two categories: Ion emission from the surfaces of metals and semiconductors tends to have a strong correlation with the work function and can be described quite well with an electron tunneling model. Ion emission from systems which show large chemical enhancement has only a weak correlation with global surface properties like the work function or the bandgap. Instead it seems to be related more to local chemical bonds and coordination numbers. A localized bond breaking picture may be more appropriate in these circumstances. © 1986.