Cathode Sputtering Research Articles

Synthesis of titanium-oxide nanoparticles with size and stoichiometry control

Ti–O nanoparticles have been synthesized via hollow cathode sputtering in an Ar–O2 atmosphere using high power pulsing. It is shown that the stoichiometry and the size of the nanoparticles can be varied independently, the former through controlling the O2 gas flow and the latter by the independent biasing of two separate anodes in the growth zone. Nanoparticles with diameters in the range of 25–75 nm, and with different Ti–O compositions and crystalline phases, have been synthesized.

The plasma levitation of droplets

We show how to levitate a liquid droplet above a plasma. Submitting a conductive droplet to a voltage larger than 50 V, we get a levitation regime that looks like the one obtained with the well-known thermal Leidenfrost effect, except that light is emitted from beneath the droplet. Spectroscopic analysis shows that this light is emitted by a cold and dense plasma and also that lines coming from the cathode plate material are present revealing a local cathodic sputtering effect. We examine the conditions for the levitation to occur and show that the levitation is essentially of thermal origin. Assuming a stationary heat transfer, we present a model that accounts well for the observed levitation conditions. In particular, stable levitation is shown to be possible for thin cathode plates only.

XPS study of TiN films formed by the electric arc technique

The phase composition of the 3 nm surface layer of Ti and TiN films is studied by X-ray photo-electron spectroscopy. The films are deposited by the electric arc sputtering of a titanium cathode in a nitrogen atmosphere under a magnetic field. It is shown that the film surface layer contains TiN, TiN x , TiO x , TiO2, and TiN x O y phases. A mechanism explaining the formation of titanium nitride films is proposed.

Cytotoxicity of noble metal nanoparticles sputtered into glycerol

Nowadays, nanomaterials belong among one of the most studies materials. Even despite the immense advantages of nanostructured materials, some studies indicate that these materials can also harmfully affect both human being and the environment. Therefore, in this study, we have focused on nanoparticle (NP) cytotoxicity in vitro. To study NPs intrinsic biological properties, we employed cathodic sputtering into glycerol for their synthesis, thus eliminating the use of toxic solvents. According to the transmission electron microscopy and dynamic light scattering measurements, we prepared non-agglomerated NPs of the following sizes: 6.1±1.0nm for gold, 4.2±0.9nm for silver, 2.5±0.6nm for palladium, and 1.8±0.4nm for platinum NPs. The cytotoxic activity of these NPs was determined by WST-1 assay using six model cell lines: human cells from hepatocarcinoma (Hep G2), human keratinocytes (HaCaT), mouse macrophages (RAW 264.7), mouse embryonic fibroblasts (L929 and NIH 3T3), and cells from Chinese hamster ovary (CHO-K1).

Fabrication and Characterization of All-Solid-state3D Li-Ion Microbatteries Based on TiO2 Nanotubes

The spectacular development of autonomous mobile systems has enhanced the race for the miniaturization of micropower sources. However, the storage performances of devices are seriously compromised when decreasing the size of the components down to the micrometer scale. This is particularly true for the development of all-solid-state microbatteries which are rapidly reaching performance limit in terms of energy and power densities. To overcome these issues, 3D microbatteries have attracted interest while remaining a technological challenge since it requires the marriage between materials science, electrochemistry, and microfabrication processes. In 2009, we proposed to use self-organized TiO2 nanotubes (ntTiO2) as a 3D negative electrode (Figure) for Li-ion microbatteries (Chem. Mater., 2009). This particular geometry is achieved by a simple electrochemical process (anodization) which improves significantly the electrochemical performance of the system. In this study will be proposed an all-solid-state 3D microbattery composed of a polymer electrolyte and a cathode material (LiFePO4) successively deposited at the surface of the nanotubes. While the nanotubes and polymer layers are obtained by electrodeposition process, the cathode material is achieved by cathodic sputtering. We will present in this work, the influence of morphology, structure and chemical composition of the cathode material on the electrochemical performance of the microbatteries in terms of areal capacity, rate capability, and capacity fading. References : [1] B. Ellis, P. Knauth, and T. Djenizian, “Three-dimensional Self-supported Metal Oxides for Advanced Energy Storage”, Adv. Mater., DOI 10.1002/adma.201306126(2014). In press (IF : 14,829) [2] N. Plylahan, M. Letiche, M. Barr, and T. Djenizian, “All-solid-state lithium-ion batteries based on self-supported titania nanotubes”, Electrochem. Commun., 43, 121, 2014 (IF : 4,425) [3] N. Plylahan, N. A. Kyeremateng, M. Eyraud, F. Dumur, H. Martinez, L. Santinacci, P. Knauth, and T. Djenizian, “Highly conformal electrodeposition of copolymer electrolytes into titania nanotubes for 3D Li-ion batteries”, Nanoscale Res. Lett., 7, 349 (2012). (IF : 2,726) [4] F. Vacandio, M. Eyraud, P. Knauth, and T. Djenizian, “Tunable electrical properties of self-organized zirconia nanotubes”, Electrochem. Commun., 13, 1060 (2011). (IF : 4,859) [5] G. Ortiz, I. Hanzu, T. Djenizian, P. Lavela, J. L. Tirado, and P. Knauth, “Alternative Li-ion battery electrode based on self-organized titania nanotubes”, Chem. Mater., 21, 63 (2009).(IF : 7,286) Figure 1

Use of dc Ar microdischarge with nonlocal plasma for identification of metal samples

The possibility of using the collisional electron spectroscopy (CES) method for the detection of atoms from metal samples is experimentally verified. The detection and identification of metal atoms from a Pt sample in the nonlocal plasma of short (without positive column) dc Ar microdischarge at intermediate pressures (5–30 Torr) is realized in this work. Cathode sputtering is used for atomization of the metal under analysis. The identification of the analyzed metal is made from the energy spectra of groups of fast nonlocal electrons—characteristic electrons released in the Penning ionization of the Pt atoms by Ar metastable atoms and molecules. The acquisition of the electron energy spectra is performed using an additional electrode—a sensor located at the boundary of the discharge volume. The Pt characteristic Penning electrons form the maxima in the electron energy spectra at the energies of their appearance, which are 2.6 eV and 1.4 eV. From the measured energy of the maxima, identification of the metal atoms is accomplished. The characteristic Ar maxima due to pair collisions between Ar metastable atoms and molecules and super-elastic collisions are also recorded. This study demonstrates the possibility of creating a novel microplasma analyzer for atoms from metal samples.

Structure and optical properties of CdS:O films by cathode sputtering

AbstractWe have studied the structure and optical properties of CdS:O films deposited on SLG (soda lime glass) substrates by cathode sputtering in the atmosphere of oxygen/argon gases. According to X‐ray diffraction (XRD) and confocal Raman scattering data, the films annealed in vacuum at temperatures above 300 °C exhibited crystalline structure of CdS. On the other hand, XRD, confocal Raman scattering, AFM (atomic force microscopy) and TEM (transmission electron microscopy) data indicated amorphous structure nano‐crystallization in CdS:O films annealed in vacuum at 400 °C. For the films, the emissions located at 3.35 eV were evident from photoluminescence measurements. The origin of this energy gap is discussed by taking into account redistribution of electronic density of states in the amorphous phase and quantum‐size effect. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Multiphase composite coatings: structure and properties

The paper discusses the results of the research into the formation of ion-plasma multiphase coatings. The types of the formed structures are found to be not so diverse, as those formed, for example, in alloy crystallization. The structures observed are basically of globular type and, more rarely, of unclosed dissipative and cellular structures. It is shown that the properties of the coating formed in deposition are largely determined by its surface energy or surface tension. Since the magnitude of the surface tension (surface energy) in most cases is an additive quantity, each of the elements of the coating composition contributes to the total surface energy. In case of simultaneous sputtering of multiphase cathodes, high entropy coatings with an ordered cellular structure and improved mechanical properties are formed.

Microstructure of the condensate formed in the vicinity of a cathode upon the deposition of Ti(N,C) coatings

The microstructure of Ti(N,C) coatings obtained in the vicinity of a sputtering cathode by condensation with ion bombardment is studied by scanning electron microscopy. Various inclusions such as drops, bubbles, pits, and traces of destruction and other structural features are found in the coating.

Suppression of Cross Contamination in Multi-Layer Thin Film Prepared by Using Rotating Hexagonal Sputtering Cathode.

In this study, single- and multi-layered thin films were prepared on a glass substrate using a newly developed rotating hexagonal sputtering cathode in a single chamber. The rotatinghexagonal sputtering cathode can install up to six different sputtering targets or six single targets in a cathode. Using the rotating hexagonal cathode, we prepared a single-layered AZO film and a multi-layer film to evaluate the performance of hexagonal gun. Cross-contamination, which is often observed in multi-layer thin film preparation, was suppressed to nearly zero by controlling process parameters and revising hardware. Energy-saving effects of five-layered glass were also verified by measuring the temperature.

СКОРОСТЬ РАСПЫЛЕНИЯ МЕТАЛЛОВ В ТЛЕЮЩЕМ РАЗРЯДЕ ПОСТОЯННОГО ТОКА, ИСПОЛЬЗУЕМОМ В АТОМНО-ЭМИССИОННОЙ СПЕКТРОМЕТРИИ

The numerical values of the cathode sputtering rate of the materials are needed to conduct the layered analysis and produce multi-matrix calibration dependencies using the method of atomic emission spectrometry glow discharge. In the current work the cathode sputtering rate in DC glow discharge was measured for 26 elements. A comparison with published data showed good consistency of the results and confirmed the need for such measurements for the specific conditions of the analysis. It was determined that the values of the cathode sputtering rate of elements are dependent on their physicochemical characteristics in a complex manner. The relationship between the cathode sputtering rate of elements with their physical and chemical properties such as atomic number, atomic weight, melting and boiling points, the sublimation energy and the energy of the crystal lattice was studied in a great detail. The periodic dependence of the values of the sputtering rate of elements from their atomic number and atomic mass was demonstrated and also confirmed by the published data. According to the P. Sigmund’s theory of sputtering solids and semi-empirical equation of the sputtering coefficient it was found that the cathode sputtering rate of the material depends on the energy of sublimation i.e. it is determined by the values of its atomic radius, melting point and density. The found relationship was confirmed by the statistical calculations using both linear and non-linear regression. The discovered dependence of the cathode sputtering rate from the physicochemical characteristics of the metal allows predicting the velocity dispersion of the material, identify erroneous measurements and evaluate the limits of applicability of the analysis method. Keyword: atomic-emission spectrometry, current direct glow discharge, the sputtering rate of metals, physical-chemical properties of metals, theory spraying solids, sputtering coefficient. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2015.19.3.003 A.L. Chicherskaya, A.A. Pupyshev Ural Federal University named after the first President of Russia B.N. Yeltsin, Yekaterinburg, Russian Federation

Influence of pressure and hydrocarbons on carbide formation in the plasma synthesis of TiC nanoparticles

We examine the influence of pressure and gas mixture composition on the preparation of nanomaterials via vacuum arc sputtering of titanium cathodes in carbon-containing media. The formation of carbide phases in various gaseous atmospheres is accompanied by the formation of the low-temperature phase α-Ti (hcp lattice), characteristic of pure titanium. Carbide formation in the plasma synthesis of TiC nanoparticles is determined by the C/H ratio in the molecules of the hydrocarbons used. To raise the yield of carbon-rich carbide phases and reduce the percentage of the residual metal in the resulting nanopowders, it is necessary to use hydrocarbons with a large C/H ratio, for example, benzene and acetylene.

XPS investigations of tribolayers formed on TiN and (Ti,Re)N coatings

TiN and (Ti,Re)N coatings were deposited on high-speed-steel substrates by a hybrid coating system composed of cathodic arc PVD and magnetron sputtering techniques. In order to keep rhenium content low (8±1.9at.%) in the coating, magnetron sputtering technique was utilized to evaporate rhenium. The (Ti,Re)N coating consisted of TiN and ReNx (x>1.33) phases. The hardness of TiN and (Ti,Re)N were 31GPa and 29GPa (±2GPa), respectively. Tribological behaviors of the samples were tested against Al2O3 balls at 21°C (RT) and 150°C (HT) by reciprocating wear technique. The tribolayers were analyzed by XPS technique. Friction coefficients of TiN were 0.56, 0.35 for 21°C and 150°C tests, respectively. Rhenium addition to TiN drastically dropped the friction coefficients to 0.22 and 0.17 for RT and HT samples. Rhenium addition also improved the wear resistance of the coating at both test temperatures. For TiN, main oxide component of the tribolayers was Ti2O3 for RT tests and TiO2 for HT tests. The oxide layer formed on (Ti,Re)N were the mixture of TiO2, TiON, ReO2 and Re2O7 for both test temperatures. Re2O7 provided very low friction coefficient to (Ti,Re)N. The findings are consistent with the crystal chemistry approach.

Detrapping of tungsten nanoparticles in a direct-current argon glow discharge

Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particles of more than a few tens of nanometres in diameter.

Synthesis and characterization of zirconium nitride coatings by cathodic arc sputtering technique

Abstract Polycrystalline zirconium nitride films (560 nm) were deposited on stainless steel (SS-316) substrates using the multi-target cathodic arc sputtering technique. Deposition was carried out under N2 reactive atmosphere (4 × 10−3 mbar) at two different temperatures, 150 and 200 °C. X-ray diffraction studies show that reflections from planes changed from (111) to (200) for deposition temperatures of 150 °C and 200 °C, respectively. Films deposited at 150 °C and 200 °C bear a critical load of 6.4 N and 6.8 N respectively, showing better adherence at higher temperature. This may be the result of film–substrate diffusion at the interface.

Wire arrays with profiled masses

Tungsten wire arrays with height-profiled masses, which are obtained by the cathode sputtering, are described. The images of wires are recorded and their diameter is determined using a scanning electron microscope. The wire arrays have such a linear mass height distribution, at which the compact three-dimensional spherically-symmetric compression due to the current implosion is possible.

Near-infrared spectrum of ZrF by intracavity laser absorption spectroscopy

The (1,1) band of the CΩ=3/2−X2Δ3/2 transition of ZrF has been recorded at high resolution using intracavity laser absorption spectroscopy. The ZrF molecules were produced using a Zr-lined copper hollow cathode sputter source with a trace amount of SF6 as a fluoride source. Molecular constants from the analysis are presented and compared with previous work.

Discharge characteristics of the DUHOCAMIS with a high magnetic bottle-shaped field

For the purpose of producing high intensity, multiply charged metal ion beams, the dual hollow cathode ion source for metal ions (DUHOCAMIS) was derived from the hot cathode Penning ion source combined with the hollow cathode sputtering experiments in 2007. To investigate the behavior of this discharge geometry in a stronger magnetic bottle-shaped field, a new test bench for DUHOCAMIS with a high magnetic bottle-shaped field up to 0.6 T has been set up at the Peking University. The experiments with magnetic fields from 0.13 T to 0.52 T have indicated that the discharge behavior is very sensitive to the magnetic flux densities. The slope of discharge curves in a very wide range can be controlled by changing the magnetic field as well as regulated by adjusting the cathode heating power; the production of metallic ions would be much greater than gas ions with the increased magnetic flux density; and the magnetic field has a much higher influence on the DHCD mode than on the PIG mode.

Effect of oxygen incorporation on the structure and elasticity of Ti-Al-O-N coatings synthesized by cathodic arc and high power pulsed magnetron sputtering

Ti-Al-O-N coatings were synthesized by cathodic arc and high power pulsed magnetron sputtering. The chemical composition of the coatings was determined by means of elastic recoil detection analysis and energy dispersive X-ray spectroscopy. The effect of oxygen incorporation on the stress-free lattice parameters and Young's moduli of Ti-Al-O-N coatings was investigated by X-ray diffraction and nanoindentation, respectively. As nitrogen is substituted by oxygen, implications for the charge balance may be expected. A reduction in equilibrium volume with increasing O concentration is identified by X-ray diffraction and density functional theory calculations of Ti-Al-O-N supercells reveal the concomitant formation of metal vacancies. Hence, the oxygen incorporation-induced formation of metal vacancies enables charge balancing. Furthermore, nanoindentation experiments reveal a decrease in elastic modulus with increasing O concentration. Based on ab initio data, two causes can be identified for this: First, the metal vacancy-induced reduction in elasticity; and second, the formation of, compared to the corresponding metal nitride bonds, relatively weak Ti-O and Al-O bonds.

A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

High power impulse magnetron sputtering (HiPIMS) has been at the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come as a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.