Magnetron Discharge Plasma Research Articles

Low-pressure high-current magnetron discharge with electron injection: From self-sputtering with multiply charged metal ions to non-sputtering with “pure” gas ions

We report our experimental investigations of the effect on the ion composition, including the ion mass-to-charge composition, of electron injection into the plasma of a high-current pulsed magnetron discharge in the ultra-low operating pressure range. We show that changing the magnetron discharge voltage by injecting additional electrons with adjustable current allows implementation of two operating modes: one with a plasma in which metal ions dominate (including multiply charged ions for certain target materials with low sputtering yield), and the other a magnetron non-sputtering mode with plasma of only gaseous ions.

The Influence of Nitrogen Flow Rate on the Structure and Properties of Mo-Hf-Y-Si-B-N Coatings

This work is devoted to the production of Mo-Hf-Y-Si-B-N coatings using magnetron sputtering with varying N2 flow rate; the analysis of magnetron discharge plasma; and the investigation of the structure, and optical, mechanical, and tribological characteristics, as well as crack resistance and oxidation resistance, of the coatings. The results show that Mo-Hf-Y-Si-B-N coatings were characterized by a dense, homogeneous structure. The non-reactive coatings had a maximum growth rate of 270 nm/min. An increase in the flow rate of N2 from 0 to 37.5 sccm led to a decrease in the growth rate by 5.4 times. Mo-Hf-Y-Si-B-N coatings were X-ray amorphous. In non-reactive coatings, the presence of Mo-Si and Mo-B bonds was revealed. The introduction of nitrogen contributed to the formation of an additional Si-N bond, an increase in the proportion of which led to an increase in transmittance. The Mo-Hf-Y-Si-B coating was characterized by a hardness value of 14 GPa. The maximum hardness of 16 GPa was observed in coatings obtained at nitrogen flow rates of 12.5 and 25.0 sccm. A further increase in the consumption of N2 to 37.5 sccm led to a decrease in hardness by 38%. The coating obtained at a flow rate of 25 sccm N2 was characterized by maximum elastic recovery of 57%, elastic strain to failure of 0.098, and resistance to plastic deformation of 0.157 GPa. An increase in nitrogen flow rate from 0 to 12.5 sccm contributed to a decrease in the wear rate of coatings under sliding friction conditions by 40%. The non-reactive Mo-Hf-Y-Si-B coating had the best oxidation resistance at 1000 °C.

Nanoscale morphology tailoring in plasma deposited CN x layers

Magnetron discharge plasma was applied for the synthesis of CN x thin layers using methane and nitrogen gas precursors. The incorporation of nitrogen in the carbon network resulted in the dramatic evolution of growth morphology: from a ‘buried’ porous layer observed at low nitrogen incorporation to aligned bundles of nanorods grown perpendicular to the substrate surface at maximum discharge power and nitrogen flow. The films deposited at the low discharge power and high nitrogen incorporation exhibited a mesoporous sponge-like morphology after vacuum annealing. Relevant physical mechanisms responsible for the formation of nano- and mesoshaped morphology are discussed in terms of the effects of internal mechanical stresses and plasma etching. In addition, the sensing properties of the sponge-like layer were preliminarily examined in water vapor and ammonia ambients. The CN x films showed enhanced sensitivity to ammonia and reverse electrical response to moisture in comparison with a nitrogen-free nanoporous carbon film, which were assigned to modification of the electronic properties of the nitridated surface.

In situ probe measurements of plasma parameters during the deposition of boron coatings by the magnetron method

The features of the probe technique are described and the results of measuring the parameters of plasma generated by a planar magnetron sputtering system with a pure boron target during coating deposition are presented. A feature of probe measurements was the use of heating the collecting surface of a single Langmuir probe. Heating led to a decrease in the electrical resistance of the boron film on the surface, which made it possible to carry out in situ probe measurements of the magnetron discharge plasma parameters during the entire process of boron coating. Keywords: plasma parameters, probe method, planar magnetron, boron films.

Зондовое in situ измерение параметров плазмы при нанесении покрытий бора магнетронным методом

The features of the probe technique are described and the results of measuring the parameters of plasma generated by a planar magnetron sputtering system with a pure boron target during coating deposition are presented. A feature of probe measurements was the use of heating the collecting surface of a single Langmuir probe. Heating led to a decrease in the electrical resistance of the boron film on the surface, which made it possible to carry out in situ probe measurements of the magnetron discharge plasma parameters during the entire process of boron coating.

Microwave plasma-assisted reactive HiPIMS of InN films: Plasma environment and material characterisation

This work focuses on the low temperature fabrication process of InN thin films via microwave plasma-assisted reactive high power impulse magnetron sputtering (MAR-HiPIMS). The influence of microwave plasma on the HiPIMS discharge process at various nitrogen flows and microwave powers was monitored and characterised through in situ diagnostics, including following HiPIMS I(V,t) curves, optical emission spectroscopy (OES), as well as performing time-resolved Langmuir probe and time-of-flight mass spectroscopy (ToF-MS) measurements. This was followed by the deposition of InN films via standard reactive HiPIMS (reference sample) and MAR-HiPIMS and their characterisation via X-ray diffraction (XRD), reflectometry (XRR), as well as scanning and transmission electron microscopy (SEM, TEM). It was found that the microwave plasma facilitates the dissociation/activation of nitrogen species and supplies seed electrons to the magnetron discharge plasma. Furthermore, the energy of the incoming ions was determined via ToF-MS, and it was possible to identify their plasma origin and temporal behaviour. The produced R-HiPIMS sample was highly metallic, with no nitride phase detected. The MAR-HiPMS film, however, was stoichiometric and exhibited (0002) direction texturing, with an optical bandgap of approx. 1.5 eV, electron concentration of 2.72 × 1020 cm−3 and electron mobility of 7.16 cm2V−1 s−1 (in the range for polycrystalline InN).

Forces applied to nanoparticles in magnetron discharges and the resulting size segregation

Two-dimensional measurements of magnetron discharge plasma parameters are used to calculate the forces applied to an isolated nanoparticle in conditions where nanoparticles are produced from cathode sputtering. Plasma spatial inhomogeneities, which are specific to magnetron discharges, also induce inhomogeneities in the charging mechanism and applied forces. It is shown that the nanoparticle transport is due to electric, thermophoretic and ion drag forces, and that the dominant one proportional to the nanoparticle size varies according to position. For a given plasma, these spatial differences explain the segregation of size in the nanoparticle deposits, which are observed inside the device.

Effect of working gas pressure on mass-to-charge composition of plasma ions in high-current planar magnetron discharge

The mass-to-charge ion composition of a planar magnetron discharge plasma has been investigated. The measurements used a modified quadrupole mass-spectrometer and a time-of-flight spectrometer. The experiments were carried out on a copper magnetron target. Argon was used as a working gas. The operating pressure was 0.15÷1.3 Pa. The discharge current was 1÷20 A with a pulse duration of 30÷50 μs. The influence of main operating parameters (discharge current and working gas pressure) on mass-to-charge composition of plasma ions was measured. The mass-to-charge composition of plasma ions in the axial direction was measured as a function of working pressure. Plasma electron temperature was measured and its effect on the mass-to-charge composition of magnetron plasma ions was estimated.

Antibacterial PLGA and PCL membranes, modified by magnetron sputtering method of copper target

The paper discusses barrier membranes which were formed from poly(lactide-co-glycolide) and polycaprolactone by electrospinning method. Then, plasma modification of membranes was carried out by magnetron sputtering of copper target in argon atmosphere. The morphology, elemental composition, mechanical and antibacterial properties of the obtained samples were investigated. Modification with copper in the magnetron discharge plasma allows maintaining the original characteristics of pristine polymeric samples and imparting antibacterial properties to them.

Mass‐to‐charge ion composition of plasma in a magnetron discharge with reactive sputtering of titanium target

AbstractIn this study, we have analyzed the ion mass‐to‐charge composition of the plasma of a magnetron discharge with a titanium target operating in various gases: argon, nitrogen, oxygen, and their mixtures. The addition of nitrogen and oxygen to argon significantly affects the ion spectrum in the magnetron discharge plasma. The increased fraction of nitrogen in the mixture of more than 15% contributes to the dominance of atomic nitrogen ions in the spectrum and leads to a strong decrease in both the plasma density and the metal (titanium) ion fraction in the plasma. The addition of more than 10% oxygen leads to the complete absence of metal ions in the spectrum. These effects are associated with the formation of nitride and oxide layers on the titanium target surface, thus inhibiting the introduction of metal ions in the plasma.

Spectroscopic diagnostic complex based on the magnetron sputtering device with a digital method of the data mining

A diagnostic complex based on a magnetron sputtering device is proposed for studying a magnetron discharge plasma parameter by optical emission spectroscopy, using two spectroscopic systems: photographic and photoelectric. Software for digital processing of the obtained emission spectra is developed. The results obtained by the two spectroscopic systems are compared.

Parameters and properties of a pulsed planar vacuum magnetron discharge

We have developed a vacuum (gasless) magnetron discharge initiated by a vacuum arc plasma. The discharge operating conditions for different magnetron target materials have been determined. The mass-to-charge plasma composition and its evolution during a discharge current pulse were measured. It is shown that, after transient processes of cathode outgassing and purification, the plasma ion component consists mainly of singly-charged ions of the magnetron target material. The measured total ion current from the vacuum magnetron discharge plasma is up to 7.5% of the discharge current.

Effects of gas pressure and discharge current on beam composition in a magnetron discharge ion source.

The magnetron discharge plasma is commonly used in thin film deposition processes, but it can also be utilized for ion beam production. We have developed and investigated an ion source based on planar magnetron discharge. We show that under certain conditions, the discharge, running in a high current pulsed mode, effectively produces plasmas with a high fraction of ions formed from the magnetron target material. The ion beam extracted from the discharge plasma and its composition were studied using a time-of-flight method. The plasma electron temperature was measured by using a double Langmuir probe. We find that the increased working gas pressure and discharge current lower the electron temperature, leading to an increased fraction of target material ions in the plasma and therefore also in the extracted ion beam due to their lower ionization potential compared to that of the working gas.

Spectral measurements in the plasma of microwave and magnetron discharges

Spectroscopic methods were used to study the parameters of a low-power (≤ 100 W) magnetron discharge plasma, as well as a low-pressure microwave discharge (6–40 Pa) in argon. It is shown that in the magnetron discharge the concentration of atoms and ions of the buffer gas (Ar) and the target material (Cu) decreases exponentially with distance from the target cathode and in the first case it occurs much more sharply. The temperature of electrons in a plasma stream, which is emitted by a discharge burning near the surface of the cathode, was estimated from the relative intensity of the spectral lines according to the LTE model and the coronal model. The values obtained in both cases were close, lying near 1 eV, and the temperature remained almost constant with the distance from the cathode. The electron temperature in the microwave discharge turned out to be almost constant over the cross section of the plasma column, while the concentration near the microwave emitter was 2–3 times higher than in the rest of the column.

Structural features and nitrogen positions in titanium oxynitride films grown in plasma of magnetron discharge

The paper addresses the results of the analysis of the structural features of nitrogen-containing titanium oxides films, deposited by reactive magnetron sputtering. The films have a nanocrystalline two-phase structure and consist of anatase and rutile crystallites, regardless of the coating deposition regimes. No traces of titanium nitride phase are found in the film and nitrogen atoms in oxide form are localized at the grain boundaries of the deposited film.

DIGITAL PROCESSING OF OPTICAL EMISSION SPECTRA OF MAGNETRON SPUTTERING PLASMA SYSTEM

To solve the actual problem of the analysis of the sputtered particles radiation during coating deposition in a magnetron sputtering system, a digital technique was proposed for processing the emission spectra of the discharge plasma. A graphic OSA application has been created, which allows obtaining qualitative and quantitative characteristics of the magnetron discharge plasma. The obtained information about the distribution of excited particles along the direction parallel to the axis of the magnetron discharge permits one to control the mode of the discharge operation and, as a consequence, the properties of the deposited coatings.

Аксиальное распределение масс-зарядового состава плазмы магнетронного разряда

Аксиальное распределение масс-зарядового состава плазмы магнетронного разряда

Operation parameters of magnetron diode for high-rate deposition of aluminum films

This article reports on the results of the detailed study of erosion of Al target in magnetron discharge plasma. It was demonstrated that the combination of middle-frequency (MF) and high impulse power (HiPIMS) power supply results in the significant increase of deposition rates of Al films by changing of sputtering yield. The MF pulse assists HiPIMS discharge to transit in a high power mode.

Synthesis of Highly Oriented Zinc-Oxide Films on Amorphous Substrates by the Method of Direct-Current Magnetron Sputtering

We describe the technology of obtaining highly oriented zinc-oxide (ZnO) films on amorphous substrates at high growth rates (up to 7 nm/s) by means of direct-current magnetron sputtering. It is suggested to optimize the substrate position with respect to magnetron and consider the floating potential to which the substrate is charged in magnetron discharge plasma as one of the main technological parameters. Electrondiffraction study of the structural characteristics of the obtained ZnO films showed that increase in the substrate temperature was accompanied by transformation of the crystallite shape from platelike to columnar.

Синтез высокоориентированных пленок оксида цинка на аморфных подложках методом магнетронного распыления на постоянном токе

AbstractWe describe the technology of obtaining highly oriented zinc-oxide (ZnO) films on amorphous substrates at high growth rates (up to 7 nm/s) by means of direct-current magnetron sputtering. It is suggested to optimize the substrate position with respect to magnetron and consider the floating potential to which the substrate is charged in magnetron discharge plasma as one of the main technological parameters. Electrondiffraction study of the structural characteristics of the obtained ZnO films showed that increase in the substrate temperature was accompanied by transformation of the crystallite shape from platelike to columnar.