Modeling of bombardment induced oxidation of silicon

Secondary ion mass spectrometry has become the preferred tool for impurity profiling primarily due to its excellent depth resolution and high detectio n sensitivity. Prerequisite in obtaining high detection sensitivity for pos itive secondary ions is the use of oxygen as primary ions. This leads to a high degree of oxidation of the sample surface, which is essential for a hi gh secondary ion ionization efficiency. Unfortunately, this oxygen bombardm ent not only leads to the transformation of the original target surface int o an oxidized layer but, as the latter requires a certain fluence before st ationary state is reached, inherently causes some nonlinearities and transi ents in the secondary ion signal and the fluence-eroded depth relation. In this work a computer code implantation, sputtering, replacement/relocation, and diffusion (ISRD) has been optimized to predict the compositional chang es of the sample surface (or altered layer formation), the sputter yields a nd the surface regression as a result of the interaction of oxygen beams wi th Si-targets. This article describes a careful reevaluation of the previou sly used version of ISRD (and the parameters contained in the program) in o rder to obtain a systematic agreement with experimental data on sputter yie lds, altered layer formation, and surface recession, and with other theoret ical predictions. (C) 2001 American Institute of Physics.