Magnetron sputtered TiO2 films on a stainless steel substrate: Selective rutile phase formation and its tribological and anti-corrosion performance

In this work, TiO₂ films on 316L stainless steel have been formed by non-reactive magnetron sputtering of TiO₂ target. The effect of a titanium underlayer on the crystalline phase of the TiO₂ film has been investigated in terms of phase evolution, film morphology, corrosion resistance, adhesion strength, hardness and tribological characteristics. Results showed that the titanium underlayer has a significant effect on the phase of the TiO₂ film. Without this underlayer, an anatase TiO₂ film is produced, in consistence with many other investigations. However, it is found that with a titanium underlayer, a rutile TiO₂ film can be directly formed on the substrate. The thickness of the interface layer affects the crystallinity of the rutile film. By controlling the underlayer thickness, the resultant rutile film crystal structure and morphology could be changed accordingly. At an optimized state, the rutile coating shows much improved adhesion, friction, wear and corrosion properties.     

Electrical memory features of ferromagnetic CoFeAlSi nano-particles embedded in metal-oxide-semiconductor matrix

Half-metallic Heusler material Co₂FeAl_0.5Si_0.5 (CFAS) nano-particles (NPs) embedded in metal-oxide-semiconductor (MOS) structures with thin HfO₂ tunneling and MgO control oxides were investigated. The CFAS NPs were prepared by rapid thermal annealing. The formation of well-controlled CFAS NPs on thin HfO₂ tunneling oxide was confirmed by atomic force microscopy (AFM). Memory characteristics of CFAS NPs in MOS devices exhibited a large memory window of 4.65 V, as well as good retention and endurance times of 10⁵ cycles and 10⁹ s, respectively, demonstrating the potential of CFAS NPs as promising candidates for use in charge storage.     

Corrosion surface protection by using titanium carbon nitride/titanium-niobium carbon nitride multilayered system

The aim of this work is the improvement of the electrochemical behavior of 4140 steel substrate using TiCN/TiNbCN multilayered system as a protective coating. We have grown [TiCN/TiNbCN]_n multilayered via reactive r.f. magnetron sputtering technique in which was varied systematically the bilayer period (Λ), and the bilayer number (n), maintaining constant the total thickness of the coatings (~ 3 μm). The coatings were characterized by X-ray diffraction (XRD), optical microscopy, electron microscopy and transmission electron microscopy assisted with selected area electron diffraction. The electrochemical properties were studied by Electrochemical Impedance Spectroscopy and Tafel curves. XRD results showed a preferential growth in the face-centered cubic (111) crystal structure for [TiCN/TiNbCN]_n multilayered coatings [1]. In this work was obtained the maximum corrosion resistance for the coating with (Λ) equal to 15 nm, corresponding to n = 200 bilayered. The polarization resistance and corrosion rate were around 8.6 kOhm cm² and 7.59 · 10^− 4 mm/year, these values were 8.6 and 0.001 times better than those showed by the uncoated 4140 steel substrate (1.0 kOhm and 0.57 mm/year), respectively. The improvement of the electrochemical behavior of the 4140 coated with this TiCN/TiNbCN multilayered system can be attributed to the presence of several interfaces that act as obstacles for the inward and outward diffusions of Cl^- ion species, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface. Moreover, the interface systems affect the means free path on the ions toward the metallic substrate, due to the decreasing of the defects presented in the multilayered coatings.     

Low temperature (< 100 °C) deposited P-type cuprous oxide thin films: Importance of controlled oxygen and deposition energy

With the emergence of transparent electronics, there has been considerable advancement in n-type transparent semiconducting oxide (TSO) materials, such as ZnO, InGaZnO, and InSnO. Comparatively, the availability of p-type TSO materials is more scarce and the available materials are less mature. The development of p-type semiconductors is one of the key technologies needed to push transparent electronics and systems to the next frontier, particularly for implementing p-n junctions for solar cells and p-type transistors for complementary logic/circuits applications. Cuprous oxide (Cu₂O) is one of the most promising candidates for p-type TSO materials. This paper reports the deposition of Cu₂O thin films without substrate heating using a high deposition rate reactive sputtering technique, called high target utilisation sputtering (HiTUS). This technique allows independent control of the remote plasma density and the ion energy, thus providing finer control of the film properties and microstructure as well as reducing film stress. The effect of deposition parameters, including oxygen flow rate, plasma power and target power, on the properties of Cu₂O films are reported. It is known from previously published work that the formation of pure Cu₂O film is often difficult, due to the more ready formation or co-formation of cupric oxide (CuO). From our investigation, we established two key concurrent criteria needed for attaining Cu₂O thin films (as opposed to CuO or mixed phase CuO/Cu₂O films). First, the oxygen flow rate must be kept low to avoid over-oxidation of Cu₂O to CuO and to ensure a non-oxidised/non-poisoned metallic copper target in the reactive sputtering environment. Secondly, the energy of the sputtered copper species must be kept low as higher reaction energy tends to favour the formation of CuO. The unique design of the HiTUS system enables the provision of a high density of low energy sputtered copper radicals/ions, and when combined with a controlled amount of oxygen, can produce good quality p-type transparent Cu₂O films with electrical resistivity ranging from 10² to 10⁴ Ω-cm, hole mobility of 1-10 cm²/V-s, and optical band-gap of 2.0-2.6 eV. These material properties make this low temperature deposited HiTUS Cu₂O film suitable for fabrication of p-type metal oxide thin film transistors. Furthermore, the capability to deposit Cu₂O films with low film stress at low temperatures on plastic substrates renders this approach favourable for fabrication of flexible p-n junction solar cells.     

磁控溅射法制备防水透湿织物的性能研究

介绍子利用磁控溅射法制备透湿织物的基本原理及方法，通过对防水透湿织物憎水性及透湿性的测试分析，发现溅射后织物的憎水性明显提高，且憎水性随溅射功能的增大而减小，随压力的增大而增在，而溅射前后的透湿性受功率和压力的影响不大。     

Optimization of an industrial DC magnetron sputtering process for graded composition solar thermal absorbing layer

Optimization of an industrial DC magnetron sputtering process for thin graded index coatings for solar thermal absorbers is reported. The optimization concerned the main processing parameters: sputtering power, argon flow, oxygen flow, and system set-up for graded control. The purpose of the optimization was to achieve a surface with efficient solar-thermal energy conversion based on the concept graded index coating, using a metal-dielectric composite coating of nickel–nickel oxide with a continuous change in composition through the film depth profile. It was found that the optimization of the materials composition could be controlled by one parameter related to the sputtering process, the relative oxygen flow RO, defined as the ratio of applied oxygen flow to the critical oxygen flow. For optimized sputtering conditions a solar absorptance of 0.92 was obtained for a single graded index coating on aluminum for RO value of 0.8. From the materials characterization it was found that this gave a graded index coating of two thick sub-layers, a top layer of nano-sized nickel oxide grains and a base layer of nano-size metallic nickel grains with a very thin interface of a mixture of nickel and nickel oxide that was almost amorphous.     

The diffusion of hydrogen and inert gas in sputtered a-SiC:H alloys: Microstructure study

The microstructure of DC sputtered amorphous silicon carbon (a-SiC:H) is studied by effusion measurements of hydrogen and of implanted inert gases helium, neon, argon and secondary ion mass spectrometry. The results suggest that the motion of inert gas atoms is controlled by the diffusion, greatly depending on a broadening of network openings. Already at carbon concentrations of 25 at%, isolated voids disappeared presumably because interconnected voids are formed. A void formation is mainly attributed to an increase in hydrogen incorporation in the samples.     

低温气相硅外延前氩微波等离子原位溅射清洗对薄膜界面的损伤

本文研究了在超高真空低温CVD（chemicalvapordeposition）硅外延中，ECR（electroncyclotronresonance）微波等离子原位溅射清洗对外延层界面损伤的情况。超高分辨透射电镜（TEM）照片表明，界面引起的损伤是较严重的，损伤层的宽度与衬底偏压的高低和溅射时间的长短直接相关。     

Analysis of semiconductor thin films deposited using a hollow cathode plasma torch

The hollow cathode plasma torch has been used for several years. One of the major applications has been the deposition of dielectric thin films. However, this technique has also been used to deposit metals where high-speed deposition is needed. It has proven to be useful in deposition of coatings onto the inside of substrates of complex shape, high-speed etching, and deposition of thin films at atmospheric pressure. In recent years, we have adapted the technique to deposit high-quality amorphous and polycrystalline semiconducting films. A large variety of measurement techniques have been employed to determine the film properties and the results are reported here.     

Durability of doped zinc oxide/silver/doped zinc oxide low emissivity coatings in humid environment

The relationship between internal stress of doped zinc oxide films and durability of doped zinc oxide/silver/doped zinc oxide low emissivity (low-e) coatings in humid environment was investigated. Aluminum, titanium, tin, chromium, silicon, gallium, magnesium, boron, barium, and calcium were chosen as a doping element in sputtering targets. Ratios of dopant/zinc in the oxide targets were 4/96-5/95 at.%. Films were formed by radio frequency sputtering. Doping of barium and calcium to the zinc oxide film led to a large increase in the internal stress. Doping of the other elements resulted in decreasing the internal stress. It was concluded that durability of the low-e coatings in humid environment closely correlated with the internal stress of the oxide layers.