RF Plasma Deposition of PEO-Like Films: Diagnostics and Process Control

Organic thin films deposited by means of radio-frequency glow discharges fed with Triglyme vapors have been investigated to explore the feasibility for deposition of organic thin films with polyethylene oxide-like features. The film chemical composition has been analyzed by means of X-ray Photoelectron Spectroscopy and FT Infrared Absorption Spectroscopy. Plasma phase diagnostics has been accomplished by means of Optical Emission Spectroscopy. It is shown that the surface density of ether carbon, which is considered the marker of the content of ethylene oxide units in the coating, decreases as the power input is increased. It is also shown that the retention of monomer structure in the film can be easily controlled in situ by actinometric optical emission spectroscopy.     

Hybrid ZnO/polymer thin films prepared by RF magnetron sputtering

Zinc oxide/poly(acrylic acid) (ZnO/PAA) multilayered hybrid films with different layer thicknesses were prepared by radio frequency magnetron sputtering. Zinc peroxide was used as precursor materials for the preparation of ZnO layers, since the zinc peroxide decomposes to ZnO during the film deposition. The films have a high transmittance in the visible region and exhibit visible photoluminescence emission. The band gap energy of the films—determined by the Tauc relationship—decreases with increasing layer thickness (3.40–3.36 eV) due to the increasing crystalline size of the ZnO particles. The morphological investigations showed that a real layered hybrid film structure formed.     

Structure and electrical properties of a-C∶H films deposited from CH4 decomposition in a low frequency discharge

a-C∶H films have been deposited from methane in a 20 KHz discharge. The Current Voltage characteristics of the plasma have been plotted as a function of the CH₄ pressure. It was shown that below 0.1 mbar the graphitic content in the films estimated from Raman Spectroscopy and Electron Energy Loss Spectroscopy is high enough to give electrical conductivity controlled by a percolation mechanism. It was also found that the a:c electrical responses of the deposited films are more sensitive to the structure than any other chemical analysis. The electrical analysis might be a good tool for structural investigations on a-C∶H films.     

Characterization of thin alumina films prepared by metal-organic chemical vapour deposition (MOCVD) by high resolution SEM, (AR)XPS and AES depth profiling

Thin alumina films deposited by metal-organic chemical vapour deposition (MOCVD) on AISI 304 substrate have been analyzed using the combination of Scanning Electron Microscopy (SEM), Auger Electron Spectroscopy (AES) and Angle Resolved X-ray Photoelectron Spectroscopy (ARXPS). Both the surface and the alumina/substrate interface region have been analyzed in terms of chemical composition and elemental distribution. Only OH-groups (bounded as AlO(OH):boehmite) have been found as an impurity in the surface region of the oxide film. No carbon was detected. Due to higher temperature deposition, the concentration of OH-groups decreased. After annealing, the oxide/substrate interface changes as a result of chromium penetration into the alumina matrix. Carbon impurities have been detected on both delaminated and annealed alumina film surfaces. Also small amounts of sulfate groups as well as Ca and C impurities have been found on delaminated alumina film after prolonged high-temperature annealing.     

Detection of mechanical effects of adhesive thin films on substrate using the modulated-temperature dilatometry (MT DIL)

The work is aimed to develop the diagnostic method for testing the state of surface coated with the wear-resistant films. Thin wear-resistant ceramic films based on titanium such as TiN, TiCN, TiAlN are deposited on working surface of cutting tools or machine elements in order to improve their tribological properties. The operation life depends mainly on the residual stresses occurring in films and the kinetics of their relaxation as a function of temperature and time. The value of the stresses is influenced by the technological conditions of film deposition and the physical and chemical properties of the substrate and film. The paper has demonstrated the usability of the modulated-temperature dilatometry (MT DIL) for recording the changes in mechanical effects of the adhesive film on the substrate as a function of temperature and time. The substrates where in the shape of cylindrical rod, 30 mm length and 3 mm diameter and of the ribbon 30 mm in length, 2 mm in wide and 120 μm thick. The thickness of the coatings was from 2 to 3 μm. The films deposition were performed using the physical vapour deposition (PVD) technique.     

DC-plasma polymerization of pyrrole

DC-plasma-polymerized pyrrole (PP-Py) films deposited on metals were extensively characterized by Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), Reflection-Absorption IR Spectroscopy (RAIR), X-ray Photoelectron Spectroscopy (XPS), Scanning Tunneling Microscopy (STM), Glow Discharge Optical Spectroscopy (GDOS), electrical conductivity (ASTM Franklin test), and contact angle measurements. TOF-SIMS and RAIR showed no spectroscopic evidence of the presence of the pyrrole ring structure in any of the plasmadeposited films. The major parameter that affected their composition was found to be the pressure. Films deposited at low pressure were less hydrogenated than those polymerized at high pressure or in remote plasma conditions. Although all deposits oxidized slowly in air, their surface energy remained low over an extended period of time. The electrical conductivity of the PP-Py films was in the range of 10⁻³–10⁻⁴ S/cm, i.e., higher than that of amorphous carbon films.     

Properties of ITO films prepared by reactive magnetron sputtering

Indium tin oxide (ITO) thin films were deposited by mid frequency pulsed dual magnetron sputtering using a metallic alloy target with 10 wt.% tin in an atmosphere of argon and oxygen. The aim of the work was to study the interdependence of structural, electrical and optical properties of ITO films deposited in the reactive and transition target mode, respectively. The deposition rate in the transition mode exceeds the deposition rate in the reactive mode by a factor of six, a maximum value of 100 nm·m min⁻¹ could be achieved. This corresponds to a static deposition rate of 200 nm min⁻¹. The lowest electrical resistivity of 1.1·10⁻³ Ω cm was measured at samples deposited in the high oxygen flow range in the transition mode. The samples show a good transparency in the visible range corresponding to extinction coefficients being below 10⁻². X-ray diffraction was used to characterise crystalline structure as well as film stress. ITO films prepared in the transition mode show a slightly preferred orientation in (211) direction, whereas films deposited in the reactive mode are strongly (222) oriented. Compared to undoped In₂O₃ all samples have an enlarged lattice. The lattice strain perpendicular to the surface is about 0.8% and 2.0% for films grown in the transition and the reactive mode, respectively. Deposition in the transition mode introduces a biaxial film stress in the range of −300 MPa, while stress in reactive mode samples is −1500 MPa.     

PE-CVD of Organic Thin Films with Controlled Surface Concentration of Carboxylic Groups

Organic thin films have been deposited onto various substrates by means of radiofrequency glow discharges fed with acrylic acid vapors. The effect of the experimental parameters on film composition has been investigated with X-ray Photoelectron and FT-IR spectroscopies; Optical Emission Spectroscopy has been carried out for plasma phase characterization. It is shown that the concentration of oxygen and carboxylic groups in the coating decreases with increasing power, while the concentration trend of CO species in the plasma increases. It is demonstrated that films deposited from acrylic acid, which can be used as functional layers for biomolecule immobilization, can be deposited with a controlled surface concentration of -COOH groups through a simple in situ monitoring of the deposition process.     

Plasma deposition of silicon nitride-like thin films from organosilicon precursors

Plasmas containing hexamethyldisilazane or hexamethylcyclotrisilazane and nitrogen or ammonia were used to deposit silicon nitride-like films at low substrate temperature (T<60°C). Optical properties (refractive index and absorption coefficient), chemical composition of the deposit and film growth rate were examined with respect to the deposition parameters (rf power, pressure and feed composition). As deposited films from ammonia containing mixtures were silicon nitride-like, contained carbon, and were nearly oxygen free. Furthermore, only Si−N, Si−H, and N−H bonds were identified in as-deposited films. The reactive Si−H bonds progressively transformed into Si−O bonds as the films were exposed to air. Films deposited from highly ammonia-diluted mixtures, high RF power and low pressure showed the highest stability with refractive indices as high as 1.8.     

Layered molybdenum oxide thin films electrodeposited from sodium citrate electrolyte solution

Molybdenum oxide thin films were prepared electrochemically onto the selenium predeposited tin oxide-coated glass substrates using 0.22 M sodium citrate (C₆H₅Na₃O₇) solution (pH 8.3) and sodium molybdate as a precursor. Cyclic voltammetry was used to determine the deposition potential effects on molybdenum compound speciation, while quantitative thin film composition was obtained from X-ray photoelectron spectroscopy depth profiles. Thin molybdenum film growth and composition was potential dependant. Predominant molybdenum species was Mo(IV) at all deposition potentials and deposition times. Optical properties of the molybdenum oxide thin films were determined using UV–VIS spectroscopy. The absorption edge varied between 560 and 650 nm, whereas optical band gap values—between 1.79 and 2.19 eV—well within the limits for solar light-induced chemical reactions.     

Electrochemical properties of composite films based on poly-3,4-ethylenedioxythiophene with inclusions of metallic palladium

The electrochemical behavior of composite Pd-PEDOT films is studied. These films are obtained by chemical deposition of Pd particles in the polymeric matrix of PEDOT (poly-3,4-ethylenedioxythiophene). Characteristics of the films are determined by means of cyclic voltammetry, faradaic impedance, microgravimetry, and energy-dispersive x-ray fluorescence analysis. Impedance spectra of composite Pd-PEDOT films, compared to the original PEDOT film, reveal a new response at potentials of −0.3 and −0.4 V in the form of a distinct semicircle, which results from processes in the electrochemical sorption-desorption of hydrogen. Weight gain during the chemical deposition of palladium in the polymer structure is estimated by mircrogravimetry. It is shown that the mass of palladium loaded in the film depends on the time of synthesis and the initial concentration of palladium ions in solution. The size of the actual surface and the average radius of dispersed palladium particles in the film are also estimated.     

Electropolymerization of polypyrrole, modified with germanium, on a passivated titanium electrode in aqueous nitrate solution: new results on catalytic reduction of protons and dissolved oxygen

Conductive polypyrrole (PPy) films and PPy films containing Ge microparticles were synthesized by anodic oxidation of pyrrole in acidic nitrate solutions using a bare passivated titanium electrode. Well-adhering black PPy films were obtained both under galvanostatic and potentiodynamic polarization. After the formation of the PPy film, during the first anodic cycle, an increase of the anodic deposition current with the number of cycles was observed, revealing the increase of conductivity of the growing film. The variations of the electrode surface area were estimated by impedance spectroscopy measurements. The kinetics of the PPy film formation is controlled by diffusion of the Py monomer in the solution. The diffusion coefficient, estimated by two different methods, was ca. 2×10^–6 cm² s^–1. The reduction rate of oxygen and protons at the Ti/PPy/Ge electrodes depends on how the Ge microparticles are incorporated in the PPy film. Optimum conditions for this incorporation are realized with thin PPy films and high Ge loading. Thermogravimetric analysis shows that the PPy film containing Ge microparticles is more thermally stable than the blank PPy film. Electronic Publication     

Preparation of Nanostructured Magnetic Films by the Plasma Jet Technique

 Magnetic films were prepared by the plasma jet technique from Fe, mumetal, and Fe/Hf or Fe/Ta nozzles. Two different plasma jet systems with different vacuum pumps were used to compare the quality of the produced films. The films prepared from a Fe nozzle in the two different equipments shows that oxygen in the residual atmosphere of the low vacuum reactor leads mainly to the formation of iron oxides. The Fe and mumetal films prepared in the high vacuum system contain only a very small amount of oxygen, as proved by chemical analysis and ferromagnetic resonance. The mumetal film, moreover, shows good soft magnetic properties and low magnetic damping. For the reactive plasma jet deposition of nanogranular Fe–Hf–O and Fe–Ta–O films, the low vacuum system was used. The films with higher oxygen content exhibit tunneling-type conductivity. In some films, superparamagnetic behaviour and spin-dependent tunneling magnetoresistance were observed.     

Quantitative Analysis of Thin Aluminium-Oxynitride Films by EPMA

 Thin films of aluminium oxynitride with diverse composition were prepared by dc-magnetron sputtering of aluminium, utilising sputtering power as well as argon, oxygen and nitrogen gas flows to vary the composition. Since film properties depend mainly on the content of incorporated oxygen and nitrogen, a method for quantitative analysis of the main constituents based on electron probe micro analysis with energy dispersive detection was developed. The excellent precision of the quantitative results for aluminium as well as oxygen and nitrogen are shown. Furthermore, a film layer analysis program was applied for the quantification of several films deposited under the same deposition parameters on silicon wafers, from 520 nm down to 40 nm thickness, showing that electron probe micro analysis with energy dispersive detection is a reliable method for quantitative compositional analysis of thin aluminium oxynitride films down to approximately 20 nm thickness. Since this method of analysis provides only bulk information, expected inhomogeneities of the depth distribution of the film components were checked by secondary ion mass spectrometry depth profiles of two thin films and correlated to the EPMA results. The thickness of the films was determined by ellipsometry. Received September 1, 1998     

Preparation of Nanostructured Magnetic Films by the Plasma Jet Technique

Summary.  Magnetic films were prepared by the plasma jet technique from Fe, mumetal, and Fe/Hf or Fe/Ta nozzles. Two different plasma jet systems with different vacuum pumps were used to compare the quality of the produced films. The films prepared from a Fe nozzle in the two different equipments shows that oxygen in the residual atmosphere of the low vacuum reactor leads mainly to the formation of iron oxides. The Fe and mumetal films prepared in the high vacuum system contain only a very small amount of oxygen, as proved by chemical analysis and ferromagnetic resonance. The mumetal film, moreover, shows good soft magnetic properties and low magnetic damping. For the reactive plasma jet deposition of nanogranular Fe–Hf–O and Fe–Ta–O films, the low vacuum system was used. The films with higher oxygen content exhibit tunneling-type conductivity. In some films, superparamagnetic behaviour and spin-dependent tunneling magnetoresistance were observed. Received October 5, 2001. Accepted November 22, 2001     

CuInSe2 thin-film deposition on flexible plastic substrate: electrolyte recirculation rate and deposition potential effects

Copper indium diselenide (CuInSe₂; CIS) layer was electrolytically plated from an aqueous medium at room temperature onto electroless nickel deposited on flexible plastic (Kapton). The CIS depositions were carried out under constant deposition potentials (−0.5 to −1.1 V vs. Ag/AgCl) and at various electrolyte flow rates (0.3 to 1.5 ml/s) under constant applied current. The resulting thin films were characterized using atomic force microscopy, energy-dispersive X-ray spectroscopy, environmental scanning electron microscopy, and X-ray diffraction. The surface morphology and the atomic composition of the deposited CIS film were found to be influenced by the deposition potential under potential control and the electrolyte recirculation rate under current control. Low electrolyte flow rates under constant current control and high cathodic deposition potential under voltage control favor the deposition of indium. CIS films of uniform deposit, smoother surfaces, and with better adhesion properties are favored by moderate electrolyte recirculation rate. At a current density of 0.6 mA/cm², the electrolyte recirculation rate required to achieve ideal CIS atomic composition was found to be 1.0 ml/s in such a setting. The crystallinity of the film improved after annealing for 2 h at 390 °C under argon atmosphere.     

电喷雾离子化技术制备FeNi(OH)x薄膜及电催化水氧化性能

采用电喷雾离子化沉积技术, 在氟掺杂锡氧化物(FTO)衬底上制备了均匀的无定形铁镍双金属氢氧化物薄膜. 与浸泡法制备的薄膜相比, 该薄膜具有更高的纯度、 更大的比表面积和较高的电催化水氧化性能, 在10 mA/cm ²时的过电位为290 mV, 并在催化反应中表现出良好的稳定性, 为可控合成高催化活性的过渡金属氢氧化物薄膜提供了一种新方法.     

Influence of the nickel content on the electrocatalytic activity of thin nanostructured Co–Te–Ni–O films

The influence of nickel addition in Co–Te–O catalytic films, obtained by vacuum co-evaporation of Co, Ni, and TeO₂ on electrocatalytic activity toward oxygen reactions in alkaline media has been investigated. Bifunctional gas-diffusion oxygen electrodes were prepared by direct deposition of catalyst films on gas-diffusion membranes consisting of hydrophobized carbon blacks. The method used allows the deposition of nanostructured films consisting of intertwined nanowires with high surface area. Thus, obtained electrodes with different atomic ratio R _(Co+Ni)/Te of the catalyst, fresh and thermally treated at 100 °C temperatures were electrochemically tested by means of cyclic voltammetry and steady-state voltammetry. It has been shown that the partial replacement of Co with about 30 at.% Ni leads to the increase in the film catalytic activity toward oxygen evolution reaction.     

Conductive thin film formation onto radiation grafted polymeric surfaces using electroless plating technique

Surface modification of polypropylene films (PP) was carried out via radiation induced graft copolymerization of 4‐vinyl pyridine (4VP) and acrylamide (AAm) to enhance the adhesion ability of the PP surface for electroless deposition of copper. Factors affecting the grafting process such as suitable solvent, comonomer composition and concentration and irradiation dose were optimized. The grafted films produced were characterized by studying their Fourier‐transform infrared (FTIR) spectra and thermal stability. The grafted films were copper‐plated by electroless deposition using Pd as the catalyst to initiate the redox reaction. The influence of catalytic activation method parameters on the plating rate were studied. Scanning electron microscopy revealed a dense and void‐free copper deposited film. The adhesion of the deposited copper film to the modified PP films was determined by measuring the tensile strength of the copper plated films. The electrical characteristics of the copper plated films in comparison with grafted films were studied. The results showed the high adhesion of the deposited copper film to the grafted PP film as well as the high electrical conductivity. Copyright © 2008 John Wiley & Sons, Ltd.     

Electroless deposition of gold into poly-3,4-ethylenedioxythiophene films and their characterization performed in chloride-containing solutions

Au-containing polymer films were obtained by electroless deposition of gold from diluted solutions of HAuCl₄ into preliminarily reduced poly-3,4-ethylenedioxythiophene (PEDOT) films. Structural peculiarities of such pristine and composite films were characterized by scanning and transmission electron microscopy methods. It was established that the gold clusters forming under such deposition appear on the outer surface of polymer films and their pores. The clusters’ sizes ranged between 30 and 100 nm depending on the time of exposition of a PEDOT film in solutions of Au(III) ions and the concentration of these ions. It was also observed that in contrast to pristine PEDOT films, cyclic voltammograms (CVs) of composite films in the presence of chloride ions show additional redox peaks resulting from oxidation of gold with formation of an insoluble product and followed by the product reduction under reversal of the potential scan direction. As a result of parallel electrochemical quartz crystal microbalance (EQCM) and CV measurements, it was also established that the number of chloride ions per one transferring electron in the gold oxidation process is near to unity. To elucidate the oxidation degree of gold in the presence of chloride ions, a special procedure of changing the electrode potential was used. It consisted of clamping the high anodic potential in the region of gold oxidation (0.97 V, Ag/AgCl) and subsequent gradual decrease of the electrode potential with a constant scan rate. Under these conditions, it was possible to completely oxidize all the gold particles containing in a composite film and find out the maximum amount of electricity consumed for the product particles’ reduction. A comparison between such data and the results obtained in EQCM determinations of the gold content in the same film led to the conclusion that the oxidation state of gold in the complexes formed is Au(III). The effects of chloride ion concentration and scan rate of the electrode potential on current responses of PEDOT–Au films were investigated. Some primary conclusions on the kinetics of the studied processes are made.