A new thermal emission cesium primary ion source for secondary ion mass spectrometer

Abstract

A thermal emission cesium primary ion source for investigation of solid-state surface layers by the SIMS method is described. The characteristics of the constructed ion source are presented. The optimal values of accelerating, focusing, and stopping potentials for the primary ions focusing system are found (Va = 4500 V, Vf = 2500 V, and Vs = 2560 V, respectively). This thermal emission cesium primary ion source is used in the secondary ion mass spectrometer constructed at the Institute of Physics of the M. Curie-Skl/odowska University in Lublin. To illustrate the application of the described ion source, the mass spectrum of GaAs secondary ions and the concentration profile of indium implanted into stainless steel at an energy of 150 keV and dose 5×1016 ions/cm2 are presented. The maximum concentration of In is at about 240-Å depth.