STRUCTURAL AND OPTICAL-PROPERTIES OF NITRIDED SILICON-OXIDE LAYERS RAPID THERMALLY GROWN IN A PURE N2O AMBIENT

Thin nitrided silicon oxide layers with thicknesses in the 3-12 nm ran ge were grown in a rapid thermal processor in a pure N2O ambient. Thes e layers were investigated by X-ray photoelectron spectroscopy, spectr oscopic ellipsometry and wet etching experiments and compared with oxi des grown in a O-2 ambient. Information about the distribution and bin ding properties of nitrogen in the oxide and its interfacial propertie s are provided. The nitrogen concentration peaks at the interface and decreases towards the oxide bulk to an extent of approximately 5 nm fo r a film thickness of 9 nm. Compared with O-2 grown oxides, the nitrid ed oxides show an enhanced saturation of Si-dangling bonds by nitrogen and a reduction of the suboxide regime. These facts may explain the u p to now reported improved electrical performance of metal oxide semic onductor devices using N2O grown oxides as the gate dielectric.