Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.

Influence of N2 Flows on Sputtered Ta(N) films: Electrical, Structural, Chemical and Optical Properties

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with a different N2 flow rate of 0, 12, 17, 25, 38, 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of the N2 flows. On the other hand, the resistivity increases, the crystal size decreases, and the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5 (130,040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, and dependent on the crystal size and crystal phase structure.

Influences of Nitrogen Flow Rate on Microstructure, Mechanical and Tribological Properties of WCN Coatings Deposited by HiPIMS

Tungsten carbide (WC) and Tungsten carbonitride (WCN) coatings are deposited by reactive high-power impulse magnetron sputtering (HiPIMS) with various nitrogen gas flow rates. The characteristics of discharge current and plasma optical emission of HiPIMS are recorded by oscilloscope (OSC) and optical emission spectroscopy (OES). The results exhibit that the peak discharge currents and the intensities of optical emission spectra lines are significantly influenced by the addition of nitrogen. The elemental concentration, microstructure, mechanical and tribological properties in ambient temperature and high temperature of deposited coatings are investigated by a wide variety of techniques such as energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nano-indentation measurement, scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and ball-on-disk tribometer. The results show that WC/WCN coatings with different microstructures, mechanical properties and tribological properties have been produced by controlling the flow rate of N2. Meanwhile, with the N2 flow rate increasing from 0 sccm to 24 sccm, (101) diffraction peak shifts to low angle. Moreover, (102) and (110) peaks’ intensities and the angle of (101) peak of β-W2C phase of the deposited WCN coatings decrease and disappear, and the average grain size decreases from 8.9 nm to 6.4 nm. XPS results show that the intensities of C=N, W–N, W–C–N, and N–O peaks increase while the intensity of C–W peak decreases. The deposited coatings change from slight columnar type to a typically dense and featureless structure, and the surface roughness decreases from Ra 11.6 nm at 0 sccm to Ra 5.7 nm at 24 sccm. The variation of nitrogen flow also plays a role in the mechanical properties of the coatings. It is found that the maximum hardness and elastic modulus of 35.6 GPa and 476.5 GPa appear at 16 sccm N2 flow rate. The results of wear tests demonstrate the addition of nitrogen slightly deteriorates tribological properties at room temperature (25 °C), but can remarkably improve tribological properties at high temperature (400 °C) of WC/WCN coatings deposited with an appropriate flow rate of nitrogen.

Immobilization of fluorides from spent carbon cathode in a copper smelting slag

The fluorides from spent carbon cathodes could be effectively solidified in a molten copper smelting slag (FeO-Fe3O4-SiO2-CaO-Al2O3) in forms of CaF2 and Ca4Si2F2O7. The results of thermodynamic analysis, chemical analysis, and XRD and EPMA analyses showed that the F solidification efficiency increased with the CaO amount and decreased with the addition of Al2O3 and SiO2. In addition, it was noteworthy that the F solidification efficiency decreased with an excessive CaO amount, which could be ascribed to the consumption of SiO2 through forming CaSiO3 and Ca3Si2O7. It restricted the solidification of the fluoride into Ca4Si2F2O7. Under the conditions of melting temperature of 1300?C, residence time of 60 min and N2 flow rate of 40 ml/min, the optimum CaO and NaF amounts were found to be 20 wt.% and 6 wt.% respectively, in which the F solidification efficiency in the copper smelting slag of FeO-Fe3O4-SiO2-CaO-Al2O3 obtained 98.35%.

Tunable Plasmonic Resonances in TiN Nanorod Arrays

In this work, titanium nitride (TiN) nanorod arrays were fabricated using glancing angle deposition in a magnetron sputtering system. The deposition parameters, including the bias on the substrate and the flow rate of nitrogen, were varied to deposit various TiN nanorod arrays. Before glancing angle deposition was conducted, uniform TiN films were deposited and their permittivity spectra, for various deposition parameters, were obtained. The effect of the deposition parameters on the morphology of the nanorods is analyzed here. The polarization-dependent extinctance spectra of TiN nanorod arrays were measured and compared. Extinction, which corresponds to the longitudinal mode of localized surface plasmon resonance, can be significantly changed by tuning the N2 flow rate and substrate bias voltage during deposition.