Oxynitride gate dielectric prepared by thermal oxidation of low-pressure chemical vapor deposition silicon-rich silicon nitride

Thin oxynitride gate dielectric films were prepared by thermal oxidation of low-pressure chemical vapor deposition silicon-rich silicon nitride at temperature ranging 850-1050 °C. X-ray photoelectron spectroscopy results indicate that the conversion of the as-deposited silicon nitride into oxynitride with different composition or oxide is feasible and the process is governed by the oxidation temperature. For sample oxidized at 1050 °C for 1 h, the nitride film was converted into silicon dioxide with 7 at.% of nitrogen at the interface and the leakage current density can be reduced by several orders of magnitude. By measuring the leakage current, the barrier height (extracted from Fowler-Nordheim plot) at the dielectric/Si interface is found to be in the range of 1.14-3.08 eV for the investigated samples.