An atmospheric pressure RF torch-barrier discharge system with flowing plasma jet channel was studied as a tool for coatings of aluminum substrates by CeOx thin films. Cerium precursors were supplied to the plasma jet in the form of aerosol of the water solution of cerium salts. CeOx thin films were obtained on the Al substrate at certain deposition conditions. Properties of deposited CeOx films were studied by electron microprobe system. Surface of the films was analyzed by XPS method. 'In situ' emission spectroscopy of active plasma jet channel was performed in order to obtain more parameters about atmospheric plasma jet channel. (C) 2003 Elsevier Science B.V. All rights reserved.

Barrier torch discharge was used for low temperature deposition of InxOy and SnOx thin films at atmospheric pressure on polymer substrates. Vapors of Sn- and In-acetylacetonat were used as growth precursors for the deposition process of SnOx and InxOy thin films. Transparent films of conductivity σSnO≈10 S/cm for SnOx and σInO≈102 S/cm for InxOy were deposited on polymer substrates under conditions when the atmospheric plasma jet directly interacted with the polymer substrate. Plasma jet excitation had to be pulse modulated in order to avoid thermal damages of the polymer substrate. SnOx and InxOy were also deposited in a different discharge mode, in which interaction of the light emitting plasma jet with the substrate did not directly occur. In this case, the films had pure adhesion and had electrical conductivity lower than σ<10−3 S/cm. The analysis by an electron microprobe system has shown that the films had chemical composition close to SnO2 and In2O3, respectively. XRD diffraction did not confirm any crystalline phase in all the deposited samples.

Accurate control of plasma microparameters at the position of the substrate is crucial factor in applications of the barrier-torch plasma source for technological purposes. We present measurements of the electron temperature Te in the RF barrier-torch discharge by means of the planar RF-compensated Langmuir probe. The probe was mounted at the substrate position. The error caused by collisions of charged particles with neutrals in the space-charge sheath around the probe (collision probe working regime) at atmospheric pressure is discussed. In order to minimize this error the single probe technique was used to acquire the probe data, which were then recalculated to get the double probe characteristic. From this the electron temperature Te has been obtained in usual manner. The Te was measured at the position of the substrate in the single- and multi-torch barrier atmospheric plasma-jet systems. Using He as a working gas Te was found to be in the interval Te=2.7–6 eV depending on the applied RF power and system configuration. The neutral gas temperature has been measured by optical diagnostics and found to be 400–800 K. The plasma of the RF barrier-torch discharge is therefore strongly non-isothermal even at such high operation pressure.

The description and investigation of a new atmospheric plasma source for the treatment and coatings of surfaces are presented in this paper. This new system is a modification of a well-known atmospheric torch discharge stabilized by a flowing channel of the working gas through an RF powered nozzle. The new version of this source prevents the transition to the regime with hot electrodes. This modification is suitable for surface and coatings applications of such substrates sensitive to overheating causing undesirable phase transition or melting. The new source called in our paper as an RF barrier-torch atmospheric discharge employs dielectrically coated nozzles instead of bare metallic ones. In that case, the plasma jet has quite different properties, as it is clear from presented experiments. The new version allowed excitation of the atmospheric plasma channel interacting with the substrate independently on the conductivity of the substrate. Simultaneously it is possible to hold the substrate temperature under atmospheric jet interaction below the limit point of aluminium melting or below an even lower limit of 80°C in a pulse-modulated mode. Extension to the multi-nozzle barrier-torch system was attained with the application of nine quartz nozzles. This multi-plasma jet excitation and its interaction was demonstrated with the substrate made of either quartz or aluminium plate, both possibly with non-flat shape. Emission spectroscopy and RF voltage and current amplitude measurements were employed in order to characterize the RF barrier-torch discharge.

The optical constants and dielectric functions of a series of samples of glassy carbon subjected to a heat treatment from 1000°C to 3000°C have been evaluated in the spectral region of 1.5–13.8 eV. In the region of 1.5–5.0 eV the method of spectroscopic ellipsometry and multiangle reflectivity with p-polarized light was applied, while in the VUV region the optical constants were evaluated by means of multiangle reflectivity with partially polarized light as well as by means of Kramers–Kronig analysis. The optical spectra are discussed, in analogy with graphite, in terms of single-electron transitions and π electron plasma excitations. The changes in the spectra by heating are ascribed to increasing average size of ordered regions and sample densification in the absence of three-dimensional graphitization.

In the recent decade an RF driven, low-pressure plasma reactor with supersonic plasma jet was developed (RPJ). This reactor was successfully used for deposition of thin films of various materials. The deposition of thin films indicates that the properties of the deposited films are dependent on the sputtering or reactive sputtering processes appearing inside the nozzle (hollow athode). The nozzle (hollow athode) fabricated of different kinds of materials and alloys works both as a cathode of the radio frequency (RF) hollow cathode discharge and as a nozzle for plasma jet channel generation as well. The RF hollow cathode discharge is a secondary discharge, which is induced by the primary RF plasma generated in the reactor chamber. The present paper deals with the experimental study of this RF hollow cathode discharge. The stress is laid on the investigation of the axial distribution of discharge parameters and sputtering processes inside the nozzle. On the base of experiments, the simple model of the axial distribution of the investigated RF hollow cathode discharge has been developed.

Thin PLZT films of various stoichiometries have been prepared by laser deposition. Waveguiding and optical properties were characterised by prism coupling method, spectroscopic ellipsometry and by transmission measurements. The composition was determined by WDX. Changes of refractive index with wavelength are discussed.

The investigation of SrTiO3: Ca, Cr, PbZr0.58Ti0.42O3 and PbTiO3 ferroelectric films on the substrate of Al2O3 and MgO single crystals respectively was performed by ESR method. Study of the SrTiO3 films with the thickness h = 17000 Angstrom and 3500 Angstrom doped by 0.1% Cr and 0.2% Ca was carried out at T = 18 K with and without illumination of ultraviolet light (lambda = 365 nm). Analysis of the observed spectra had shown that there were two Cr3+ ESR lines with g-factors 1.977 and 1.974 in the thick film whereas in thin film there was line with g = 1.974 with higher intensity than that in thick Film. Calculations lead to the conclusion that the line with smaller g-factor belongs to Cr3+ centers nearby films surface. Small intensity line with g = 2.002 revealed in the films most probably belongs to O- center. Its intensity increases after illumination, but it conserves even without illumination contrary to the bulk samples. ESR spectra of PZT and PT films were recorded at T = 77 K and 300 K for different orientations of magnetic field. Analysis have shown that the spectra origin is Cr, Mn, V and Fe impurity ions. The influence of the revealed defects and impurities on the properties of the films is discussed.

A low pressure pulsed RF supersonic plasma jet system (RPJ) has been used for deposition of CNx thin films. The aim of the CNx thin films deposition was an application for tribological coatings. Chemical composition, mechanical and optical properties of deposited CNx films have been measured. The obtained parameters were found to be similar to those of CNx films prepared by DC magnetron sputtering. The deposition rate for the CNx films prepared in RPJ reactor was of approximately 2 μm/h. During the deposition process, the substrate temperature did not exceed 250°C, as required for certain kinds of machine tribological coatings. A strong correlation between DC bias magnitude, nitrogen concentration and mechanical properties was found. The value of the substrate bias VDC=−100 V was found to be optimal for deposition of hard CNx films with maximum microhardness H=22 GPa. The films with the highest microhardness had the lowest atomic concentration of nitrogen. Analogous correlation has been found in ‘Diamond Relat. Mater. 7 (1998) 417’, although the deposition method and conditions were quite different. The chemically active plasma has been investigated in the RF supersonic plasma jet channel during the deposition process by means of ‘in situ’ emission spectroscopy. The mechanism of CNx formation has been studied as well.

The fluorescence detector, a component of the AUGER project, is designed to observe fluorescent light generated in interactions of high energy cosmic rays with nitrogen atoms in the Earth's atmosphere. This article present several designs of optical filters transmitting in the range 300 nm- 420 nm, where the fluorescent light is emitted. Two approaches are proposed: a system of thin dielectric layers and a combination of suitable glass plate. Quality of different filters is determined according to the value of transmittance in the required wavelength range, the shape of the transmittance curve at the edge of the transmitting window, long-term stability as well as feasibility and cost of their mass production. Selected types of filters were prepared, their parameters measured and compared with predicted values.

The paper deals with the theory of measurement of an object in-plane velocity (object as a rigid body) by means of the method availing the statistical properties of the speckle field (speckle pattern). At first, the general theory of determination of the small deformation tensor of an elementary area of an object surface using the electronic speckle correlation in the optically free space and in the image field is briefly mentioned. Furthermore, the philosophy of measurement and interpretation of measurement is presented and the analysis of sensitivity and accuracy is also shortly done.

The chemical vapor deposition (CVD) process of a-C:H films from methane and argon gas mixtures in an electron cyclotron resonance (ECR) microwave plasma has been studied. The formation of a-C:H films in a wide range of basic parameters has been investigated. The basic parameters are the following: the total pressure of the working gas mixture, the composition of the gas mixture, the magnitude of microwave power absorbed in a plasma, the location of the substrate LECR-S with respect to the position of ECR and substrate material (Si, ceramic). We found that extremely low or zero growth rate of the a-C:H films takes place in the cases when (i) the substrate is placed in the ECR plane or its close vicinity and (ii) a high microwave power is used; the latter situation occurs when the power is about 300 W or greater. The increase in deposition rate takes place under the increase of the LECR-S distance or under the decrease of the microwave power. The deposition rate of a-C:H films on the ceramic substrate was higher than that on the silicon substrate for all values of operating pressure. These peculiarities are explained in terms of additional heating of Si substrates by microwave power absorption outside the ECR region. A later (latent) parameter should be taken into account in the analysis of the deposition process and choice of the substrate material. The mechanism leading to a very high growth rate of a-C:H polymer-like films is discussed.

A plasma-chemical reactor with a multi-plasma-jet RF hollow-cathode system has been developed for the deposition of alloy and composite thin films. Two primary plasma-jet channels and one secondary plasma channel were created in the volume of the reactor. High-density plasma flowing in these plasma-jet channels is generated inside the nozzles. These work simultaneously as RF hollow cathodes. An RF hollow cathode discharge is generated in these nozzles and is subsequently blown out of the reactor, creating flowing plasma jets. These jets were used for the deposition of SiGe and ZrCN thin films as an example of the deposition of alloy and composite thin films with this system. Co-sputtering or reactive co-sputtering of the nozzle material using high-density RF hollow-cathode plasma was applied for the deposition process. Control of the composition of the thin films was accomplished by setting the relative distance between the nozzle outlets without changing the plasma density inside the RF hollow cathodes. The composition of films was investigated with an electron microprobe system equipped with an X-ray microanalyser. This apparatus allowed quantitative analysis of the films. The stoichiometric homogeneity of the films was studied with this technique. Optical emission spectroscopy was used to investigate the secondary plasma-jet channel.

Hydrogenated carbon nitride and carbon nitride films were deposited by ECR plasma-assisted CVD (PACVD) and rf reactive magnetron sputtering. Film composition (N/C ratio), growth rate (Vg) and microhardness H were investigated depending on the type (dc or rf) and the level of substrate bias in the range 0 to −200 V. As was revealed, the ion bombardment influences the composition and growth rate of carbon nitride films during their deposition. An increase in rf bias voltage up to −200 V results in a decrease in Vg up to zero, while the dependence of N/C on rf bias value reveals a peak at about −130 to −150 V. Analysis of Raman spectra for both film types indicates a decrease in size of the film-forming clusters and simultaneous arrangement of atoms towards graphite-like structure with increasing ion bombardment intensity. From the resemblance of Vg, N/C and Raman spectra behavior to the variation in ion bombardment characteristics, it can be concluded that the ion bombardment effect reveals common features for two essentially different deposition methods, whereas the film growth mechanisms are strongly different for these deposition techniques and substantially influence the composition and growth rate of the films. The microhardness of CNxHy films increased with increasing ion bombardment intensity, but did not exceed 7000 N/mm2. These effects are related to the film microstructure evolution under the ion bombardment and sp2 nature of the chemical bonds in the film-forming clusters.

The investigation of the films with the thickness h=1700nm and 350nm doped by 0.1%Cr and 0.2%Ca on Al2O3 single crystal substrate was performed by ESR method. The spectra were recorded at T=18K with and without illumination of ultraviolet light (lambda=365nm). Analysis of the observed spectra had shown that there were two Cr3+ ESR lines with g-factors 1.977 and 1.974 in the thick film whereas in thin film there was line with g=1.974 with higher intensity than that in thick film. Calculations lead to the conclusion that the line with smaller g-factor belongs to Cr(3+)centers nearby films surface. Small intensity broad line with g=2,011-2.021 which was revealed under light illumination in the films most probably belongs to O- center. The influence of the revealed defects and impurities on the properties of the films is discussed.

In the present paper the Langmuir probe technique was applied for plasma monitoring in the Ar and n-hexane mixture plasma during the polymerisation process. The experiments were performed in a stainless steel DC magnetron reactor with a planar magnetron cathode. Within the investigated range of the gas pressure, no time-stable condition of the discharge was found. The regular oscillations, of a frequency of approximately 32 kHz, were observed in the Ar and 20% n-hexane mixture at the total pressure of 10 Pa and the discharge current of 8 mA. The experimentally obtained probe characteristics were used to determine the density and the average energy of electrons. In the DC magnetron stainless steel reactor the electron average energy in the Ar and n-hexane mixture plasma was about one order of magnitude smaller than in the case in which the working gas inside the reactor was the pure Ar.

CNx coatings were deposited by DC magnetron sputtering at lower constant N-2 pressure 0.1 Pa. Nitrogenation of samples was controlled by increase in the DC current. It led a decrease in the nitrogen content N/C in the films, but increased their microhardness. Evaluation of optical properties combining spectroscopic ellipsometry (1.5-4 eV) and the VUV reflection spectroscopy (4-14 eV) by means of Kramers-Kronig analysis showed increase of the pi-plasmon resonance peak, which indicates enhancement of amount of pi-bonded electrons. It is linked with increase of sp2 hybridization. The optical energy gap values indicate semimetallic properties of the CNx films. A shift in the epsilon(2)(omega) maximum corresponding to sigma-sigma* electron transitions in carbon demonstrates deeper band structure changes in highly nitrogenated samples. (C) 1999 Elsevier Science S.A. All rights reserved.

Electron cyclotron resonance (ECR) plasma activated CVD in CH4+N2 gas mixture has been used to grow thin CNxHy films on steel or Al–Si alloy. The composition, optical and mechanical properties of the films deposited at various process conditions were investigated by electron microprobe analysis (EPMA), IR spectroscopy and microhardness measurements. It was shown that the DC bias does not influence substantially the films properties and such films have a high nitrogen content (N/C∼0.6) and polymer-like structure. The RF bias changed drastically all the films properties. RF biased films had a small nitrogen content (N/C∼0.2), were rather harder 4000–7000 N/mm2 (i.e. 4–7 GPa), all the bands on the IR spectra of the films became very weak and some of them disappeared. This effect is explained by the ion bombardment influence, which may be effectively realised for dielectric CNxHy films only at RF biased substrate. Variation of RF biased CNxHy film properties is related to the destruction of their polymer-like structure under the ion bombardment and formation of a highly disordered structure of the film on the base of graphite-like clusters containing the carbon and nitrogen atoms. The tribologically best CNxHy coatings prepared by the described method of ECR plasma activated CVD were achieved under RF bias URF about −100 V and for lower ratio of N/C less than 0.2 in the films.