Simulation of the initial transient of the Si+ and O+ signals from oxygen sputtered silicon by means of independent models on sputtering and secondary ionization

The Si+ and O+ signals, as obtained in secondary ion mass spectrometry (SIM S) analysis of silicon when using oxygen as the primary species, pass throu gh an initial transient region before reaching the stationary state. We sim ulate this transient zone to check a phenomenological model for the seconda ry ionization of sputtered atoms. The simulation is split into two parts: t he sputtering of neutrals obtained from implantation, sputtering, relocatio n/replacement, and diffusion, simulations and their subsequent ionization. The ionization phenomena are also described by some ad hoc fitting function s with which the SIMS measurements are better approached than with the mode l. The fitting functions and the model outputs are verified with experiment al secondary ionization data. (C) 2001 American Institute of Physics.