Electron beam-assisted growth of ultrathin silicon oxynitride films on Si(100) at moderate temperatures: in situ determination of composition and gap width

Abstract

Exposure of a Si(100)-2x1 surface to low pure NO gas pressures (≤ 8x10 −6 mbar) at moderate temperatures (room temperature (RT) - 600 °C) leads to the formation of an amorphous passivating oxynitride layer (thickness ∼ 0.5 nm). However, we show that low energy (100 eV) electron bombardment of the surface, during exposure to NO, induces the formation of amorphous ultrathin (≤ 2 nm) silicon oxynitride films having different elemental compositions. At RT, oxygen-rich films were grown, while nitrogen-rich layers were formed at 600 °C. The thickness and the composition or the gap of the resulting insulating layers have been in situ deduced from Auger Electron Spectroscopy (AES) or Reflection Electron Energy Loss Spectroscopy (REELS) measurements respectively, using a standard single-pass Cylindrical Mirror Analyzer (CMA).