The mass spectrum of a tin liquid metal ion source

Tin is an important metal with new potential applications regarding the fabrication of novel devices. In this work the mass spectrum of a tin liquid metal ion source (LMIS) is studied in detail. Sn++ was found to dominate in the beam both over Sn+ and over cluster ions. By studying the behaviour of the relative intensities of Sn+ and Sn++, as a function of emission current, the conclusion is reached that both Sn+ and Sn++ are emitted as a result of direct field-evaporation from the liquid surface. Cluster ions form by ion impact-aided droplet disintegration.