Ion Beam Sputtering for High Resolution Depth Profiling

Abstract

  The damage and the in-depth distributions of Argon atoms or Oxygen atoms in Si(100) surface after Ar⁺ or O₂⁺ ion beam sputtering were investigated by using Medium Energy Ion Scattering Spectroscopy and Dynamic Monte Carlo simulation. The primary ion energy was 0.5 keV and the primary ion beam direction was varied from surface normal to glancing angle. It was observed that the damage layer can be minimized with 0.5 keV O₂⁺ and Ar⁺ ion bombardments at the incident angle of 80° from surface normal. In the case of 0.5 keV Ar⁺ ion beam sputtering at the surface normal incidence, the maximum atomic concentration of Ar atoms was 6 at% at the depth of 2 nm, while at the incident angle of 80°, the in-depth Ar distribution cannot be observed. In the case of 0.5 keV O₂⁺ ion beam sputtering at surface normal incidence, the surface is continuously swelled to ～1.5×10¹⁶ O₂⁺ ions cm^-2 ion dose owing to an incorporation rate of oxygen higher than the sputtering rate of Si. Dynamic Monte Carlo simulation reproduced the in-depth concentration distribution of Ar atoms and Oxygen atoms, quantitatively.