THICKNESS AND COMPOSITIONAL NONUNIFORMITIES OF ULTRATHIN OXIDES GROWN BY RAPID THERMAL-OXIDATION OF SILICON IN N2O

Thin dielectrics grown on 4 in. and 6 in. silicon wafers in a pure N2O ambient using the rapid thermal process (RTP) are nonuniform. For two different flow geometries, the measured thickness of the thin dielectric close to the gas inlet is found to be greater than that found away. The chemical composition of the thin dielectric near the wafer edge is shown to be different than that found near the wafer center. Results of electrical testing across the silicon wafer of metal-oxide-semiconductor (MOS) capacitors fabricated with these thin dielectrics are correlated with the chemical composition nonuniformity. The decomposition of N2O may be responsible for the measured thickness and compositional nonuniformities.