Mechanism of silicon dioxide decoupled plasma nitridation

The mechanism for decoupled plasma nitridation of silicon dioxide thin films is investigated using experimental measurements of nitrogen depth profile and integrated plasma equipment - surface physics modeling. Results show that neutral N atoms and N₂⁺ ions are the primary agents responsible for dielectric film nitridation. N atoms adsorb at the dielectric surface and diffuse into the bulk film. N₂⁺ ions are deposited in an ion-implantation like manner and broaden the nitrogen profile considerably. The surface nitrogen concentration can be enhanced by increasing the plasma source power. Nitrogen diffusion coefficient in the dielectric film decreases with increasing film thickness.