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Magnetron sputtering erodes the target non-uniformly, leading to the formation of a circular deep trench called groove, which will have a direct effect on plasma and thin film deposition properties. These effects are highlighted by measurements of the electrical parameters and the deposition rate. Moreover, the measurements of the discharge electrical equivalent plasma impedance indicate clearly, that the occurrence of the target erosion effects is related to the ion sheath thickness formed in front of the eroded target groove. The effects of the eroded target, on discharge parameters, appear from a certain pressure transition range (0.1–0.5 Pa). The eroded target lowers the self-bias voltage by 50%, reduces the deposition rate by almost 40% and increases the ion current density at the substrate. The use of an eroded target improves the plasma confinement, and the electrical equivalent impedance becomes less capacitive and more resistive. Our results show that measuring the plasma impedance might be used as a tool for monitoring the groove formation. [ABSTRACT FROM AUTHOR]

The plasma characteristics of 355 nm and 532 nm laser ablation of Al-doped ZnO (AZO) target were studied by optical emission spectroscopy and ion probe measurements. Zn emission lines were measured detected at above 0.9 J/cm 2 for 355 nm laser and 0.6 J/cm 2 532 nm laser respectively, while Al species were detected only above 2 J/cm 2 . The kinetic energy of the ions was slightly higher for 532 nm ablation as compared to 355 nm ablation. In addition, the ablation of 532 nm laser was affected by the large laser penetration depth. When deposited at 2 and 4 J/cm 2 , AZO films with energy band gap of 3.45–3.6 eV were obtained. Nanostructured AZO films were obtained by 355 nm laser ablation but nano and micro-particulates were formed in 532 nm laser ablation. The large micron-sized particulates were Al-rich thus affecting not only the morphology but also the stoichiometry of the films. It is thus concluded that despite a lower ablation and growth rate, 355 nm generated Zn, O and also Al species at lower threshold fluence that can lead to high quality AZO films at room temperature. [ABSTRACT FROM AUTHOR]

Abstract: Using high power impulse magnetron sputtering (HiPIMS) technique, amorphous FeCuNbSiB thin films have been deposited. Results concerning the influence of certain sputtering conditions (working gas pressure, average power, and pulse duration) on the particle transport and deposition rate of the films are presented. The pulse voltage was set to a constant value of −1kV, for relatively short pulses (4–20μs) with a repetition frequency in the range of 0.05 to 2kHz, attaining a maximum cathode power density of about 5kW/cm2. Tunable Diode-Laser Absorption Spectroscopy (TD-LAS), Tunable Diode-Laser Induced Fluorescence (TDLIF), Time Resolve-Optical Emission Spectroscopy (TR-OES), fast imaging and electrical investigations (voltage and current waveforms) have been used to investigate the plasma composition and its change in front of the target and onset of the self-sputtering regime. For an average power of 30W and pulse duration of 4μs, the argon pressure around 1.33 Pa assures an optimal transport of the particles between the target and substrate. For the same pulse duration, the deposition rate increases almost proportionally with the average discharge power, while, for the same average power, the deposition rate decreases with pulse duration increase due, in most part, to onset of the self-sputtering regime. [Copyright &y& Elsevier]

Abstract: In this work, tetramethylsilane-based plasma-enhanced chemical vapor deposition (PECVD) processes were studied, and the deposited silicon-containing diamond-like carbon (DLC) films were analyzed. The main goal was to identify correlations between plasma parameters and the film structure and properties. The electron temperature, gas temperature, and hydrogen and silicon particle densities in these plasmas were calculated using optical emission spectroscopy measurements; the electron density and elastic electron collision rate were determined using self-excited electron resonance spectroscopy. The elemental composition of the films was determined by glow discharge optical emission spectroscopy, and the hardness and Young's modulus were characterized using nanoindentation. The plasma parameters of the gas temperature and electron temperature revealed stringent correlations with the film composition and properties and thus can already monitor the resulting properties during the deposition process. Increasing the gas temperature using power variation leads to reduced incorporation of silicon and hydrogen in the diamond-like carbon films with a simultaneous increase of the film hardness. However, a gas temperature increase using a higher gas flow rate results in a decrease in the film hardness and an increase in the silicon and hydrogen contents. These results are promising concerning the use of plasma parameters for process control of CVD processes. [Copyright &y& Elsevier]

Abstract: This study reports on the control of intrinsic stress in MoCr films deposited by ionized magnetron sputtering using a secondary plasma created through a radio-frequency (13.56 MHz) antenna. The efficiency of the additional antenna has been investigated by optical emission spectroscopy for a MoCr target. It appears that ionization of the sputtered species is significantly enhanced compared to a conventional magnetron sputtering. Moreover, by controlling the substrate bias, the RF power on the antenna and the discharge gas pressure (argon), the ion energy and flux can be strongly modified. Therefore, we have the ability to act on composition, growth rate, microstructure and residual stress of the deposited film. Indeed, the films exhibit residual stress varying from compressive value (−3.4 GPa) to tensile one (1.7 GPa). In particular, only by varying the RF power on the antenna, a wide range of tensile and compressive stress can be obtained without affecting the chemical composition of the films. These results will be useful when elaborating stress-engineered micro-objects such as micro-springs. [Copyright &y& Elsevier]

Abstract: Zirconium nitride thin films were synthesized by a microwave electron cyclotron resonance (MW-ECR) plasma enhanced unbalanced magnetron sputtering (PE-UMS) technique. The results of plasma diagnostics by an electrostatic probe indicate that the electron temperature decreases with increasing nitrogen flow rate. The substrate ion current initially increases as the nitrogen flow rate increases at a low flow and then decreases with increasing nitrogen flow. The nitrogen concentration in the films increases and the grain size decreases while the N2 + ion density increases. The metastable Zr3N4 phase occurs as the N/Zr atomic ratio reaches 1.4. The films become amorphous as the N/Zr atomic ratio is higher. The corresponding microhardness of the deposited films increases from 22.5 GPa to the maximum of 26.8 GPa, and then decreases linearly to 19.8 GPa as the N2 flow rate increases from 8 to 14 sccm. The mechanism of the influence of the plasma characteristics on the microstructure and mechanical properties of the deposited films were discussed. [Copyright &y& Elsevier]

Abstract: The work is devoted to the investigation and development of innovative plasma diagnostics method based on mutual application of plasma immersion and time-of-flight approaches for ion charge state and mass measurements. It is experimentally demonstrated that despite the presence of long tails in ion current waveform measured by Faraday cup, there is a way to increase the spectrometer resolution by several times. The current pulse FWHM equal to 170 ns was reached, that gave a possibility to use this approach for ion charge state and mass measurement for plasma with any element of the Periodic Table. [Copyright &y& Elsevier]

Abstract: Time-resolved Langmuir probe measurements have been employed to investigate the temporal development of the plasma properties, such as electron and ion density, electron temperature as well as the floating and plasma potential, during Modulated Pulsed Power Magnetron Sputtering (MPPMS). A chromium target was sputtered with an average power of 650W in an argon atmosphere (0.53Pa) employing two steps of excitation of the discharge which was realised by altering the modulation frequency of the voltage supplied to the target. The overall pulse duration was kept at 750μs and a repetition frequency of 100Hz was used. Three distinct stages of the discharge, namely the initial and the second step of excitation as well as the transition region which connects both stable states, were found. Maximum electron densities up to 7×1011 cm−3 were obtained during the transient phase. [Copyright &y& Elsevier]

Abstract: Thin films of cubic boron nitride (c-BN) can be produced by various PVD and PECVD techniques under several prerequisites referring reportedly to the growth temperature, stoichiometry of the deposited films, and energy impact of the growing surface during film deposition. For reactive magnetron-sputtering in Ar/N2 gas mixtures and using a hexagonal boron nitride (h-BN) target, we examined the values of substrate bias necessitated for the deposition of c-BN in correlation with the composition of sputter gas at a fixed radio-frequency (r.f.) target power of 500W and a substrate temperature of 400°C. The threshold substrate bias was found to minimize at the [N2]:[Ar] ratio of about 1:16. At low nitrogen concentrations i.e. [N2]:[Ar]<1:32, c-BN growth was not achieved. The results are correlated with the variation of plasma parameters for different [N2]:[Ar] gas concentration ratios as evaluated from Langmuir double-probe measurements. Influence from the film stoichiometry is also shortly commented. [ABSTRACT FROM AUTHOR]