Absolute elastic differential cross sections are presented for electron scattering from nitrous oxide (N,O) for incident energies between 5 eV and 80 eV. Integral and momentum transfer cross sections have also been determined by extrapolation of the differential cross section data to 0" and 180". Particular attention has been paid to the measurement of differential cross sections below lOeV as in this region only one earlier measurement at 5 eV has been reported. Previous works investigating vibrational excitation have shown evidence for a negative ion resonance near 8 eV, however no manifestation of this resonance has been found in the elastic scattering channel in this work. A comparison is also made between the differential cross sections of N,O and CO2 as previously it has been found that the cross sections of isoelectronic molecules (i.e. N2 and CO) exhibit very similar shapes and values.

The charge-trapping properties of the high-permittivity titanium oxide-hafnium silicate-silicon dioxide ͑TiO 2 / HfSiO / SiO 2 ͒ gate stacks have been studied using scanning capacitance microscopy. From the bias stress examination of the gate stacks, we concluded that there were electron traps within the films, and these trap densities increased with an increase in the oxidation temperature used for the fabrication of TiO 2 top dielectrics. Furthermore, we found that the distribution of these charged defects was inhomogeneous within the gate stacks. These results are attributed to Ti diffusion through the dielectric layers, which caused electrical defects within the gate stacks.

Equivalent oxide thickness ͑EOT͒ scaling, as well as improved interface properties, of metal/higher-k gate stacks for the sub-1 nm region was achieved using a TiO 2 / HfSiO / SiO 2 layered dielectric structure. Ti diffusion into the bottom oxides was found to form electrical defects, which lead to an increase of leakage current, fixed charge, interface trap density ͑D it ͒, and reliability degradation of the gate stacks. By controlling Ti diffusion and terminating Ti-induced defects using forming gas annealing, we successfully obtained a superior interface property ͑D it = 9.9 ϫ 10 10 eV −1 cm −2 ͒ and reduced gate leakage ͑J g = 7.2ϫ 10 −2 A / cm 2 ͒ at the 0.71-nm-EOT region.

Lanthanum (La) incorporation into Hf-silicate high-permittivity (high-k) gate dielectrics was conducted using a physical-vapor-deposition (PVD)-based in situ method. PVD-grown metal Hf, La, and Hf–La alloys on base SiO2 oxides received in situ annealing to form high-quality HfLaSiO dielectrics, and subsequent deposition of metal gate electrodes was carried out to fabricate advanced metal/high-k gate stacks without breaking vacuum. The in situ method was found to precisely control La content and its depth profile and to tune the effective work function of metal/high-k stacks. Remarkable leakage current reduction of almost seven orders of magnitude compared with conventional poly-Si/SiO2 stacks and excellent interface properties comparable to an ideal SiO2/Si interface were also achieved at an equivalent oxide thickness of around 1.0 nm. Our x-ray photoelectron spectroscopy analysis revealed that, as previously suggested, effective work function modulation due to La incorporation is attributed to the interface dipole (or localized sheet charge) at the bottom high-k/SiO2 interface, which is crucially dependent on the La content at the interface. Moreover, it was found that high-temperature annealing causing interface oxide growth leads to redistribution of La atoms and forms the uppermost La-silicate layer at the metal/high-k interface by releasing the dipole moment at the bottom high-k/SiO2 interface. Based on these physical and electrical characterizations, the advantages and process guidelines for La-incorporated dielectrics were discussed in detail.