Angular and Energy Dependence of the Ion Beam Oxidation of Si Using Oxygen Ions from a Duoplasmatron Source

Oxygen ions with energy in the range 4-15 keV O⁺ were used to synthesize surface oxide layers by bombarding Si samples at different angles of incidence with respect to the surface normal. High-resolution Rutherford backscattering spectroscopy and channelling were used to determine both the stoichiometry and thickness of the surface oxides. In particular, the effect of energy on the critical angle for the formation of SiO₂ was determined. The thickness of the oxide layers were also simulated using the PROFILE and TRIM codes. A stoichiometric oxide was obtained for angles of incidence of <25°, irrespective of the ion energy used. The critical angle for oxide formation was found to be largest for the highest ion energy. The thickness of SiO₂ varies linearly with the ion energy, and correlates very well with PROFILE and TRIM code simulations.