Subnanometre depth resolution in sputter depth profiling of Si layers using grazing-incident low-energy O₂⁺ and Ar⁺ ions

The sputter damage profiles of Si(100) by low-energy O₂ ⁺ and Ar⁺ ion bombardment at various angles of incidence were measured using medium-energy ion scattering spectroscopy. It was observed that the damaged Si surface layer can be minimized down to 0.5-0.6 nm with grazing-incident 500 eV Ar⁺ and O₂⁺ ions at 80°. To illustrate how the damaged layer thickness can be decreased down to 0.5 nm, molecular dynamics simulations were used. The SIMS depth resolution estimated with trailing-edge decay length for a Ga delta-layer in Si with grazing-incident 650 eV O₂⁺ was 0.9 nm, which is in good agreement with the measured damaged layer thickness.