The purpose of this work is to demonstrate that operations using the plasma biasing technique in pulsed filtered cathodic vacuum arc (PFCVA) enable an energy-enhanced in deposition process for the high quality of tetrahedral amorphous carbon (ta-C) thin films (high sp3 content, denser, and very low surface roughness). The effect of anode bias potential on the energy distribution function of C+ ions, including the topography, microstructure, chemical state, and density of ta-C films, was systematically investigated. It was found that the plasma biasing technique can increase the average energy of C+ ions, but nevertheless, the ion flux and ion density decreased. The ion energetically enhanced deposition during PFCVA facilitates the densification of the films up to 3.30 g center dot cm-3 for substrate with the grounded substrate condition, and up to 3.22 g center dot cm-3 for substrate with the floating substrate condition. In addition, the films surface roughness and sp3 content significantly depend on the average ion energy.

This paper presents a comparative study of amorphous silicon (a-Si) thin films deposited by three different techniques: direct current magnetron sputtering (DCMS), bipolar pulse magnetron sputtering (bipolar pulse MS) and high-power impulse magnetron sputtering (HiPIMS). The structurafl properties of the a-Si films with a thickness of-similar to 112 nm were characterized by X-ray reflectivity and Raman spectroscopy. The surface morphology, optical and mechanical properties of a-Si films with a thickness of similar to 400 nm were investigated using a field emission secondary electron microscope, an atomic force microscope, spectroscopic ellipsometry and nanoindentation. It was found that for the same time-averaged discharge power, the deposition rate of the HiPIMS method was lower compared to DCMS and bipolar pulse MS. The a-Si film prepared by HiPIMS method had the lowest root mean square roughness of 0.65 nm and the highest density of 2.21 g/cm(3). These results are consistent with the highest refractive index (400-700 nm) of 3.66 and a hardness of 9.09 +/- 0.19 GPa in the film, indicating that the HiPIMS method produces denser films than the DCMS and bipolar pulse MS methods. The amorphous silicon thin films fabricated by HiPIMS have the potential to improve the structural and mechanical properties for high performance thin film semiconductor applications.

An anode layer ion source, or an ALIS, is classified as a gridless ion source that produces a high-energy ion beam for either surface etching or thin film deposition. In the present work, the energy distribution functions of the ions generated in a circular ALIS were measured using a retarding field energy analyzer (RFA). Consequently, the average density and energy of the ions arriving at the ground surface were determined for the given range of process parameters. The IEDFs show two different groups of ions, namely, a narrow low energy group and a broad high energy group. The low-energy ions are probably generated in the background plasma and accelerated via the cathode sheath adjacent to the RFA. High-energy ions, on the other hand, are possibly generated in the discharge channel and gain an energy of up to 0.7eVanode through the anode sheath. The variations in average ion energies and densities as a function of process conditions could be due to the potential profile between the source and the ground surface.

The flux of negative oxygen ions in a dc reactive magnetron discharge has been measured using a specially developed magnetic-filtering probe. The gridded probe which operates as a retarding field analyzer has a magnetic filter attached to the front entrance to suppress plasma electrons entering the device. As a result, the fluxes of unmagnetized negative ions with energies of higher than similar to 10 eV can arrive to an ion collector and contribute to the detected probe current. During the oxide mode of Ti-Ar/O-2 magnetron sputtering discharge, the measured negative ion flux is considered to be contributed by the sputtered O- ions generated at the target surface and the plasma O- ions created in the discharge volume. However, in specific discharge conditions, the sputtered ions are likely to dominate in the measured flux signal. As a result, the yield of the sputtered O- ions and associated energy flux can be examined. The magnetic-filtering probe could potentially be employed as a real-time diagnostic tool to monitor the sputtered O- flux as well as the oxide state of the target surface during reactive magnetron sputtering processes.

The effect of adventitious contamination on total-electron-yield XANES analysis of carbon species of diamond-like carbon (DLC) films was investigated. XPS and XANES measurements on a DLC sample with different amounts of contamination were carried out in the same analysis chamber. The amount of contamination was adjusted by 0.5-keV Ar-ion sputtering. The sp(2)-bonded atoms deduced from the XANES spectra was found to vary with amount of the surface contamination. Bombardment DLC films with 0.5-keV Ar ions might cause damage to the sp(2) hybridization in DLC.

Transparent electrodes (TEs) are essential components in many optoelectronic devices. Although indium tin oxide (ITO) has an excellent trade-off between optical transparency and electrical sheet resistance, it still suffers from several drawbacks, including the increasing cost of indium and poor long-term flexibility due to work hardening. This work presents the development of a new class of TEs based on ultrathin ZnO/Ag/ZnO samples in which Ag films with different film thickness are used as the metallic interlayer. XRD, XPS depth profiling, UV–vis-NIR spectrophotometer, Hall effect measurement, and a four-point probe system were used to characterize the properties of the fabricated films. Optimum thicknesses of Ag and ZnO top layer films were determined as those having high optical transmittance and good electrical conductivity. The main objective of this work has been to investigate how the density of the Ag interlayer in ZnO/Ag/ZnO film samples affects their optical and electrical properties. Silver layers prepared using DC magnetron sputtering (DCMS) have different densities to those prepared using high power impulse magnetron sputtering (HiPIMS). The optimum figure of merit at 3.53 × 10−3 Ω−1 was achieved for ZnO (0.6 nm)/Ag (9 nm)/ZnO (20 nm) multilayer films in which the Ag interlayer was fabricated using the HiPIMS method.

X-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) were employed for the investigations of diamond-like carbon (DLC) films prepared by highpower impulse magnetron sputtering technique (HiPIMS). The measurements were done ex-situ, i.e. the prepared DLC samples were exposed to air during transferring from the deposition to analysis chambers. It is inevitable that the surface of the samples was contaminated by absorbed air molecules. XPS analyses revealed that the main surface contaminants are carbon and oxygen, which introduce the difficulties for the determination of carbon species in the DLC films. In this work, a complementary XAS technique was used for analyzing carbon species in the DLC films. It was found that the DLC film contain more sp2 than sp3 carbon. The discrepancy in the sp2/sp3 ratio from the two techniques is different as a result of the difference in depth/surface sensitivity.

An ionized physical vapor deposition technique for thin ferromagnetic films is proposed. The technique is based on high power impulse magnetron sputtering (HiPIMS) with positive discharge polarity. A gapped-target was employed as the cathode of the magnetron. By applying positive HiPIMS pulses to the anode, sputtered particles inside the magnetron source were ionized and extracted through the gap. Using a discharge current with a peak of about 13 A, an ion flux in the order of 1021 m−2s−1 was obtained at a distance of 45 mm from the magnetron. In addition, deposition rates of up to 1.1 Å/s for nickel films were achieved using a 30 Hz repetition rate and 300 µs pulse width.

PandaX III is a High Pressure gaseous xenon Time Projection Chamber for Double Beta Decay detection. It will be installed deep underground in the JinPing Laboratory in Szechuan province, China. During its first phase the detector will operate with 200 kg of enriched 136Xe. The detector consists of a mesh cathode in the center of a cylindrical vessel and Micro-Bulk Micro-Megas at both ends to read out the drifting charges. The active volume is surrounded by an array of electrodes to shape the homogeneous drift field, the so called field cage. Gaseous xenon, however, is a poor dielectric. It would require in excess of 10 cm to safely stand off the HV between these electrodes and the grounded detector walls. Nearly a quarter of our available xenon would be wasted in this dead space. In a new design the electric field outside the field shaping is totally contained in a cylinder 1.6 m diameter and 2 m long. For manufacturing two 50 mm thick Acrylic plates are bend into half cylinders and bonded together. The outside surface of the cylinder is covered with a copper mesh as ground plane. The gap between field cage and detector vessel can be now reduced to 1 mm, and this gap is field free. The amount of wasted xenon is reduced by a factor 100. The field shaping electrodes and the resistive divider network are mounted on 5 mm thick Acrylic panels suspended on the inside of the field cage. This design is realized with low radioactivity materials.

An inverted gapped-target magnetron sputtering device has been developed for deposition of ferromagnetic thin films under energetic conditions. The main feature of this technique is that the discharge is driven by a positive voltage relative to a grounded target situated away from the magnetic field. As a result, it is possible to efficiently sputter ferromagnetic materials and have a source of energetic plasma ions available in the ion-assisted deposition process at the substrate. Electrical probe measurements have shown that the density and the most likely energy of the ions arriving to the grounded substrate is approximately 10(16) m(-3) and 200 eV, respectively. In the sputtering of nickel films, no cracking of the film surfaces was observed, without substrate heating or biasing. The energetic ions available with this inverted configuration are thought to be the main contributor to the observed enhancement in overall film qualities. (C) 2017 Elsevier Ltd. All rights reserved.

A cathodic vacuum arc plasma (CVAP) system was constructed at Chiang Mai University to be used for the deposition of nanostructured and nanocomposite thin films. Various CVAP sources were developed, such as with a single or dual-rod cathode. A range of features were implemented including “triggerless” arc initiation, macroparticle filters, and negative substrate bias, which can be pulsed. In our experiments, various kinds of conductive materials were used as cathode in modes of single- or multi-element film deposition. The film deposition could be done under several types of gas atmospheres with various pressures. These technical developments allowed us to produce diverse types of thin and nanostructured films. Examples of applications include Mo-containing tetrahedral amorphous carbon films, diamond-like carbon (DLC) films, nano-structured carbon films and C–Mo nanocomposite films, C–Ti and C–Pt hybrid films, Ti-nitride films, hybrid Ti–Ni films, etc. The films were applied to wafers used in microelectronics, and to components in fuel cells.

Amorphous carbon (a-C) films were deposited on Si(1 0 0) wafers by a filtered cathodic vacuum arc (FCVA) plasma source. A negative electrical bias was applied to the silicon substrate in order to control the incident energy of carbon ions. Effects of the electrical bias on the a-C/Si interface characteristics were investigated by using standard Rutherford backscattering spectrometry (RBS) in the channeling mode with 2.1-MeV He2+ ions. The shape of the Si surface peaks of the RBS/channeling spectra reflects the degree of interface disorder due to atomic displacement from the bulk position of the Si crystal. Details of the analysis method developed are described. It was found that the width of the a-C/Si interface increases linearly with the substrate bias voltage but not the thickness of the a-C film.

It is well known that the structure and properties of diamond-like carbon, and in particular the sp3/sp2 ratio, can be controlled by the energy of the condensing carbon ions or atoms. In many practical cases, the energy of ions arriving at the surface of the growing film is determined by the bias applied to the substrate. The bias causes a sheath to form between substrate and plasma in which the potential difference between plasma potential and surface potential drops. In this contribution, we demonstrate that the same results can be obtained with grounded substrates by shifting the plasma potential. This plasma biasing (as opposed to substrate biasing ) is shown to work well with pulsed cathodic carbon arcs, resulting in tetrahedral amorphous carbon (ta-C) films that are comparable to the films obtained with the conventional substrate bias. To verify the plasma bias approach, ta-C films were deposited by both conventional and plasma bias and characterized by transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). Detailed data for comparison of these films are provided.

A dual-cathode arc plasma source was combined with a computer-controlled bias amplifier to synchronize substrate bias with the pulsed production of plasma. In this way, bias can be applied in a material-selective way. The principle has been applied to the synthesis of metal-doped diamondlike carbon films, where the bias was applied and adjusted when the carbon plasma was condensing and the substrate was at ground when the metal was incorporated. In doing so, excessive sputtering by energetic metal ions can be avoided while the sp(3)sp(2) ratio can be adjusted. It is shown that the resistivity of the film can be tuned by this species-selective bias; Raman spectroscopy was used to confirm expected changes of the amorphous ta-C:Mo films. The species-selective bias principle could be extended to multiple material plasma sources and complex materials.

Metal-containing tetrahedral amorphous carbon films were produced by dual filtered cathodic vacuum arc plasma sources operated insequentially pulsed mode. Negatively pulsed bias was applied to the substrate when carbon plasma was generated, whereas it was absentwhen the molybdenum plasma was presented. Film thickness was measured after deposition by profilometry. Glass slides with silver padswere used as substrates for the measurement of the sheet resistance. The microstructure and composition of the films were characterizedby Raman spectroscopy and Rutherford backscattering, respectively. It was found that the electrical resistivity decreases with an increaseof the Mo content, which can be ascribed to an increase of the sp2 content and an increase of the sp2 cluster size.

Diamond-like carbon (DLC) films were deposited on stainless steel disc substrates by plasma immersion ion implantation and deposition (PIII&D) technique. Ar, CH4 and C2H2 gas were used as the working gases and discharged by radio frequency at 13.56 MHz. During the implantation and deposition process the plasma discharge was monitored by optical emission spectroscopy in order to analyze the state of the chemical species presented in the plasma. Ion implantation (Vbias = -20 kV and –10 kV) process served to produce a graded interface between the DLC films and the substrate material. Deposition (Vbias = -5 kV) process using a gas mixture of C2H2/Ar with a ratio of 1:1. The structure information of the DLC films was evaluated by Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The composition of the DLC films and the thickness was measured by Rutherford backscattering spectrometry (RBS). The tribological properties were analyzed using a pin-on-disk tribometer and a microhardness tester, respectively. It was found that the DLC film was 0.8 μm thick with a hardness of 2.54 GPa and had good friction properties. Raman spectra appeared as G-band and D-band centered at 1550 cm-1 and 1418 cm-1, respectively. FTIR analysis observed the sp3 C=H2 asymmetric and sp2 C=C bond at 2928.73 cm-1 and 1667.10 cm-1 peak.

This paper describes the development of a plasma system for textile treatment. The SF6 plasma was applied to improve hydrophobic property of Thai silk. It was produced by an inductively coupled 13.56 MHz RF discharge in a cylindrical stainless steel chamber of 31.2 cm diameter and 42.5 cm long. The plasma was confined by arrays of permanent magnet buttons. The operating pressure was at 1, 3, 5 and 7 mTorr while the RF power was varied from 25 to 75 W. The plasma parameters were characterized by two techniques, the single movable Langmuir probe and optical emission spectroscopy (OES). The absorption times and contact angles were utilized to analyze the result of the treated sample.The SF6 plasma parameters were measured at the center of the chamber. The electron temperature was about 3-5 eV and the ion density was 1.0-3.5 x 10(10) cm(-3). The optical emission spectroscopy results show the mixture of fluorine ion inside the plasma. The hydrophobicity improvement of silk was achieved. The treated samples reach the limit of the absorption times at 180 min and increase the contact angle to 130-140 degrees. These results show a significant increase in the hydrophobic property compared with the untreated sample. The optimum operating conditions were at an RF power of around 50 W and a pressure of 3-5 mTorr. (c) 2004 Elsevier B.V. All rights reserved.