Experimental and theoretical studies of the build-up of an oxide layer during oxygen ion bombardment of silicon

Detailed experimental studies of the build-up of a stoichiometric SiO₂ layer in silicon substrates during bombardment with 15 keV ¹⁸O⁺ and ¹⁶O⁺ ions have provided a valuable insight into the implantation, sputtering and desorption processes that occur during the formation of a continuous surface oxide layer. The use of the two isotopes also enables the dependence of the oxygen-sputtered ion yield to be evaluated and hence enables the experimentally measured profiles to be stimulated. The initial 15 keV O⁺ implantation and subsequent secondary-ion mass spectrometry depth profiling using 3 keV Xe⁺ have been simulated using the IMPETUS code and excellent agreement has been obtained. The code takes into account sputtering, atomic mixing, collective effects to conserve packing density constraints, stoichiometry factors and desorption effects.