Investigation of plasma oxynitridation of Si(001) by NH3/N2O/Ar remote plasma processing

Plasma oxynitridation of Si(001) was carried out by NH3/N2O/Ar remote plasma generated from a toroidal-type remote plasma source in a commercial 8-in. plasma-enhanced chemical vapor deposition (PECVD) system. Oxynitridation experiments of Si were performed by varying the NH3/N2O/Ar gas flow ratio and plasma exposure time at the substrate temperature of 500 °C. Time evolution of the layer thickness, chemical composition, and bonding characteristics of the silicon oxynitride layers were investigated by various analytical methods including X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry and high-resolution transmission electron microscopy (HR-TEM). The results showed a formation of the silicon oxynitride layers with the film thickness of 1.5-2.0 nm and different compositions depending on the experimental conditions. N content incorporated in the silicon oxynitride increases but the growth rate of silicon oxynitride layer decreases with increasing NH3/N2O gas flow ratio.