NITROGEN CONCENTRATION-DEPENDENCE ON BORON-DIFFUSION IN THIN SILICON OXYNITRIDES USED FOR METAL-OXIDE-SEMICONDUCTOR DEVICES

The effect of nitrogen concentration on boron diffusion in silicon oxi des (oxynitride) used for metal-oxide-semiconductor structures was inv estigated. The oxynitrides, which were formed by oxidizing thin, therm ally grown nitrides, contained uniform amounts of nitrogen. The boron diffusion coefficients in the oxynitrides were determined, and experim ental and simulated results were compared. The diffusion coefficients have an Arrhenius relationship to each concentration of nitrogen, and are smaller in higher nitrogen concentrations. A 25% concentration of nitrogen exhibited an oxynitride diffusion coefficient at least two or ders smaller than that of SiO2,. The higher the nitrogen concentration was, the larger the activation energy was. The diffusion coefficient data is useful for evaluating the boron penetration of various types o f oxynitrides, including nitrided oxides. An empirical diffusion model is proposed in order to explain the experimental data qualitatively.