XPS Analysis of Oxide Formed on the Surface of Co-28Cr-6Mo-1Si Alloy Oxidized at 550°C

This work investigated the influence of oxidation durations on the formation of oxide on the surface of wrought Co-28Cr-6Mo-1Si alloy. The iso-thermal oxidation was individually performed in air at 550°C for 4, 12 and 24 h. For comparison, the surface of the non-oxidized Co-28Cr-6Mo-1Si alloy was concurrently examined. The chemical compositions of the non-oxidized and oxidized alloys were principally analyzed via X-ray photoelectron spectroscopy (XPS). The XPS results revealed that the surface of the non-oxidized alloy enriched in Cr-oxide. After oxidation treatment, the Co-oxide, existing as Co2+ state was observed coexisting with two Cr-oxide states, Cr3+ and Cr4+. The low concentrations of Mo6+ were also observed on the oxidized alloy surface. With the increase in oxidation durations, the Co-oxide was suppressed by Cr-oxide. The XPS depth profile analysis indicated that the thickness of the oxide film increased with increasing the oxidation duration.

Formation mechanism of plasmonic silver nanohexagonal particles made by galvanic displacement reaction

Multi-element XPS depth profile analysis made clear that Ag nanoscale hexagonal columns formed by newly-discovered galvanic displacement reaction are covered with Cu compounds which prevent Ag columns from fusion, resulting in stable hotspots.

Ultra Thin SiNX on a-Si In Situ Hot-Wire CVD by Decomposing NH3 Gas

The fabrication of ultra thin silicon nitride (SiNX) layer (< 2 nm) on amorphous silicon (a-Si) in-situ hot-wire CVD by decomposing ammonia (NH3) gas is reported. Approximately 1.5 nm thin SiNXis formed by nitridation of 40 nm thick a-Si for 10 min at substrate temperature of 250 °C. The amorphous phase of SiNXformed on a-Si and a-Si layer deposited on c-Si wafer is identified by Raman spectroscopy. The formation of ultra thin SiNXby nitridation of a-Si at 250 °C is confirmed by X-ray photoelectron spectroscopy (XPS) depth profile measurement of SiNX/a-Si structured film. The report indicates that the HWCVD method can be used for fabricating superlattice structures consisting of ultra thin SiNXlayers (< 2 nm).

Effect of Low Power Deposition and Low Oxidation Temperature on the Interfacial and Structural Properties of sputtered HfO2 Gate Dielectrics

ABSTRACTHafnium dioxide gate dielectrics, prepared by DC magnetron with low-power sputtering deposition followed by a low-temperature thermal oxidation, show greatly improved interfacial and electrical properties. Ellipsometry and X-ray photoelectron spectroscopy (XPS) measurements show a good stoichiometric HfO2 thin films with a refractive index of 1.9 and an Hf:O ratio of 1:2. The results obtained after analysis, quantification and calculation through XPS depth profile method, angle resolved XPS and interface modeling by XPS data processing software suggest a development of a complex three layer dielectric stack, including hafnium dioxide layer, a narrow interface of hafnium silicate and broad region of oxygen diffusion into silicon wafer. The measured dielectric constant of the HfO2 was about 22. The film band-gap was found to be ∼ 5.2 eV.