Argon-nitrogen Gas Mixture Research Articles

Surface temperature of a 2 in. Ti target during DC magnetron sputtering

Recently, there has been increasing interest in the use of hot targets to enhance the sputter deposition of materials. However, the actual temperature of the target surface is normally not known. In this work, we directly measured the radial distribution of the surface temperature of a MAK 2 in. Ti water-cooled target using a type K thermocouple during the operation of the sputtering system. Principally, the measurements were made as a function of applied DC power and argon gas pressure. Given the importance of chemical reactions between the gas and the target during reactive sputtering, we have also measured the target temperature as a function of the nitrogen concentration in an argon-nitrogen gas mixture. A few of the reactively sputtered samples were analyzed by x-ray photoelectron spectroscopy.

Effect of Ar-N2 Ratio on Morphology and Electrochemical Properties of Lithium Electrodes Manufactured by Magnetron Sputtering

This article discusses the possibility of regulating the morphology of lithium electrodes manufactured by magnetron sputtering from a liquid-phase target on stainless steel substrates by a composition of argon-nitrogen gas mixture. Lithium electrodes produced by magnetron sputtering in an impurities-free argon gas, have a polycrystalline structure. The sizes of lithium crystals depend on the thickness of fabricated electrodes and vary from units to tens of microns. An increase in the content of nitrogen in a mixture with argon leads to a decrease in the size of lithium crystals and, in the limiting case, to the formation of a microcrystalline structure of lithium electrodes. The effect of nitrogen on the morphology of lithium electrodes is explained by the formation of lithium nitride on the surface of growing lithium crystals, which disrupts the regularity of condensing lithium layers and hinders the growth of crystals. Lithium electrodes fabricated by magnetron sputtering of lithium in argon-nitrogen mixtures have better electrochemical properties compared to electrodes produced in pure argon.

Peculiarities of pulsed laser deposition of thin InGaAsN films in an active background gas atmosphere

III-V-N compounds are a promising class of solid solutions that have the prospect of being used in optoelectronic devices operating in a wide spectral range up to 3 μm, as well as for increasing the efficiency of photodetectors, lasers in fiber-optic communication lines and telecommunication systems. In this work, the features of various methods for obtaining new III-V-N semiconductor materials are investigated. Thin InGaAsN films were obtained by pulsed laser deposition on GaAs (100) and Si (100) substrates in an active background gas atmosphere. Pulsed laser deposition of thin InGaAsN films was carried out using an In0.02Ga0.98As target in an atmosphere of a highly pure argon-nitrogen mixture at a pressure of 2, 5, and 10 Pa. The source of laser radiation was an AYG:Nd3+ laser with a wavelength of 532 nm (second harmonic), laser radiation energy density of 2.3 J/cm2, pulse repetition rate of 15 Hz, and pulse duration of 10 ns. The substrate temperature was 350 °C, the deposition time was 60 minutes. It is shown that the surface of thin films is textured with microdroplets. It has been established that microdroplets on the surface of a thin film are formed by metallic indium. It has been established that the distribution of indium microdroplets over the film surface is mainly ordered in the form of lines. This phenomenon can be explained by the presence of misfit dislocations. The average size of microdroplets on the surface of the InGaAsN film on GaAs (100) was about 30 nm, and their density did not exceed 0.076 μm–2. For comparison, in films obtained on Si substrates at a pressure of 2 Pa, the highest microdroplet density was 0.26 μm–2. The lowest density of microdroplets on the surface (0.17 μm–2) was noted in samples of a thin film of InGaAsN on Si (100) obtained at a pressure of 10 Pa. It is noted that the intensity of the local phonon vibrational mode LVM InN at a frequency of 430 cm–1 increases with increasing pressure of the argon-nitrogen mixture during pulsed laser deposition in the Raman scattering spectra of InGaAsN films on Si. In the Raman spectra of InGaAsN films on Si, second-order phonon modes LVM InN and LVM GaN were detected at frequencies of 450 cm–1 about 470 cm–1, respectively. This confirms the presence of nitrogen in a thin InGaAsN film obtained by pulsed laser deposition. It is shown that an increase in the pressure of the argon-nitrogen gas mixture during pulsed laser deposition contributes to an increase in the nitrogen concentration in thin InGaAsN films on Si. It has been established that the nitrogen concentration in InGaAsN films obtained at a pressure of 10 Pa on GaAs (100) and Si (100) substrates differs insignificantly and amounts to 1.9 % and 1.8 %, respectively. The presented results will make it possible to create highly efficient photoelectric converters and photodetectors for the near and mid-infrared range up to 3 μm based on the obtained InGaAsN thin films.

Microstructure and Stress of Ni/C Multilayer Films Prepared by Reactive Sputtering

Magnetron-sputtered Ni/C multilayers with a periodic thickness below 4 nm are difficult to produce, and reactive sputtering with nitrogen is a feasible method. The effects of nitrogen on the reflectivities of Ni/C multilayers were investigated. Pure argon and three mixing ratios of 4%, 8%, and 15% nitrogen-argon gas mixture were used as the working gas. For all Ni/C multilayer samples, each contains 40 bilayers. The nominal structure has a periodic thickness of 3.8 nm, with a ratio of the thickness of the Ni layer to the periodic thickness of Г = 0.39. The results of grazing incidence X-ray reflectivity (GIXRR) measurements indicate that reactively-sputtered Ni/C multilayers have a lower interface width and higher specular reflectance. It was shown in transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) measurements that a periodic layered structure can still be clearly observed in Ni/C multilayers with pure argon, but with quite rough interfaces between the adjacent layers. For Ni/C multilayers with the mixing ratio of 4% nitrogen-argon gas mixture, it is found that the interfaces between Ni and C layers become smoother and sharper. Additionally, nitrogen incorporation can reduce the mobility of Ni atoms, which decreases the threshold thickness that Ni layers would become continuous. This may be also a reason which accounts for the better interface quality of reactively-sputtered Ni/C multilayers. Meanwhile, Ni/C multilayers deposited with a nitrogen-argon gas mixture have lower stress due to the reduction in Ni adatom mobility.

Tribological characteristics of samples made from titanium alloy VT5 nitrided in plasma glow discharge

The effect of nitriding of VT5 alloy (3.7115) in the plasma of a glow discharge excited in a hollow cathode on its tribological characteristics in pairs with different materials in jet fuel TS-1 and under dry sliding conditions has been studied. For research and tribological tests, samples of VT5 alloy were nitrided in the plasma of a glow discharge excited in a hollow cathode at a temperature of 975 ± 15 °C and a pressure of 58 ± 2 Pa in a nitrogen-argon gas mixture with a nitrogen content of 78 vol. %. Tribological tests were performed on a friction machine 2070 SMT-1 according to the scheme "cube-roller". Tests under conditions of sliding with jet fuel TS-1 were performed at a load of 200 N. The sliding speed during the tests was 1.3 m/s, and the test time was 75 s. The test under dry sliding conditions was carried out at a load of 100 N and a sliding speed of 0.785 m/s. The test time was 30 minutes. It is shown that the nitrided VT5 alloy in friction pairs with several materials has rather low wear values (≤ 2.26 × 10–6 mm3/Nm), as well as a coefficient of friction at the level of 0.08 to 0.12.

Fabrication of NO-containing calcium phosphate coatings via direct introduction of argon-nitrogen-mixtures applied in reactive RF-magnetron sputtering

Nitric oxide plays a crucial role in the human body, due to its regulatory effect on vascular tone, cell adhesion, vascular permeability, etc. The introduction of nitric oxide into calcium phosphate coatings can increase the bioactivity significantly. This article proves the possibility of deposition of nitric oxide-containing calcium phosphate coatings on titanium substrates. Therefore, various argon-nitrogen working gas mixtures were used in reactive radiofrequency magnetron sputtering of hydroxyapatite. The amount of nitric oxide increases with the concentration of nitrogen in the working gas mixture. Coatings characterized by a higher deposition rate of nitric oxide are showing also a higher roughness of the surface. Due to the adjustment of these deposition parameters, the morphology of the coating surfaces can be regulated.

Study on the Microstructure and Friction Characteristics of ZrN Coatings Containing Cu and Si

To improve the mechanical properties of coatings used in cutting tools and automotive parts, ZrCuSiN coatings were deposited in an argon-nitrogen gas mixture using magnetron sputtering at various nitrogen gas flow rates. The structural properties of the fabricated ZrCuSiN coatings were investigated using the friction coefficient, wear coefficient, coating hardness, and elastic modulus via nano indentation and ball-on-disk friction testing. The surface morphology of the coatings was analyzed using scanning electron microscopy (SEM). The structural characterization results show a typical face-centered cubic ZrN structure with peaks in the (111) and (200) directions. The highest hardness was obtained for coatings deposited at a nitrogen gas flow rate of 5 sccm, and the coefficient of friction was lowest at a nitrogen gas flow rate of 3 sccm. It was found that the high hardness of the coating causes wearing of the counterpart. In contrast, a 3 sccm coating with stable hardness and coefficient of friction was found to be the most optimal.

Effect of the Channel Inclination Angle on Convective Mixing Caused by Instability of Mechanical Equilibrium of Ternary Gas Mixture at Isothermal Diffusion

The peculiarities of a convective regime aroused due to instability of mechanical equilibrium of a ternary helium–argon–nitrogen gas mixture at isothermal diffusion are experimentally investigated. The effect of the inclination angle of diffusion channel on the intensity of convective flows is considered. The intensity of the partial transport of components in the inclined channel was measured at increased pressures. The nonlinear dependence of the mixing rate of components on the inclination angle is discovered. It is established that the observed transport of components atypical for diffusion is possible at a certain composition of the gas mixture.

Влияние энергии ионной стимуляции на удельное электросопротивление углеродных пленок, полученных методом импульсно-плазменного осаждения в атмосфере азота

In the paper, thin carbon films deposited by pulse-plasma ion-assisted sputtering of graphite in argon-nitrogen gas mixture are discussed. The EELS and electron diffraction showed the graphite phase enlargement with the ion assistance energy increase. Application of ion assistance during the deposition process made it possible to control the films specific resistivity, altering it from 10^5 to 10^2 Ohm⋅cm.

Optical emission spectroscopy study of the influence of the low-energy electron beam parameters on the content of neutral atomic nitrogen in the beam plasma

Optical emission spectroscopy was used for studying the influence of plasma generation mode (continuous and repetitively-pulsed), electron beam parameters (current 2-14 A, energy of 100-300 eV) and pressure of nitrogen-argon gas mixture (0.3-3 mTorr) on the relative content of neutral atomic nitrogen in the beam plasma.

Substrate and annealing temperature dependent electrical resistivity of sputtered titanium nitride thin films

We have studied the electrical resistivity and the temperature coefficient of resistance (TCR) of titanium nitride (TiNx) thin films deposited by radio-frequency (RF) reactive magnetron sputtering from a high purity titanium target in a nitrogen-argon gas mixture environment with high nitrogen-to-argon ratio (20:1). The electrical resistivity and TCR are measured from room temperature to 500 °C for films deposited with substrate temperatures of 25 °C, 350 °C and 600 °C. After deposition, some films are annealed at 600 °C for four hours either with or without breaking the vacuum. The structural stability of the films was examined by measuring electrical resistivity from room temperature to 500 °C repeatedly up to four cycles. Selected films were further characterized by Rutherford backscattering, X-Ray diffraction, and Raman spectroscopy. Our results show that RF sputtered TiNx films with good electrical resistivity and temperature-stable TCR for high-temperature applications of conductive diffusion barrier and temperature sensing can be produced. We conclude that high substrate temperature, high annealing temperature, and annealing without breaking the vacuum yield optimal structural stability and electrical resistivity. High mass density is also important to prevent oxidation and degradation of electrical performance.

Magnetron sputtered Hf–B–Si–C–N films with controlled electrical conductivity and optical transparency, and with ultrahigh oxidation resistance

The paper deals with Hf–B–Si–C–N films deposited onto Si and SiC substrates using pulsed magnetron co-sputtering of a single B4C–Hf–Si target (at fixed 15% Hf and 20% Si fractions in the target erosion area) in argon–nitrogen gas mixtures. We focus on the effect of the nitrogen fraction in the gas mixture (in the range from 0% to 50%) and of the voltage pulse length (50 μs and 85 μs with the corresponding duty cycle of 50% and 85%, respectively) on the structure and properties of the films. We show that an increasing nitrogen fraction in the gas mixture and consequently in the films (up to 52 at.%) results in a strong amorphization of the film structure, decrease in the film hardness, and rapid rise in the electrical resistivity and the optical transparency of the films. Very high oxidation resistance in air even up to 1500 °C is demonstrated for two sufficiently hard (20–22 GPa) Hf–B–Si–C–N films: the electrically conductive Hf7B23Si22C6N40 film and the optically transparent Hf6B21Si19C4N47 film, both with a contamination level < 3 at.%. The results are important for designing high-temperature protective coatings of electronic and optical elements, and sensors for severe oxidation environments.

Preparation and characterization of CrN thin film by DC reactive magnetron sputtering

In this work, the DC reactive magnetron sputtering were used to deposit the chromium nitride (CrN) thin films on silicon (100) wafers and 304-type stainless steels in argon-nitrogen gas mixture at room temperature. The effect of nitrogen partial pressure ratios [%PN2 = PN2/(PN2+PAr)×100] on the microstructural were studied. The crystal structure of the prepared CrN films were analyst by X-ray diffraction. For the physical morphological analysis, atomic force microscopy and field-emission scanning electron microscopy were used. An element analysis of the CrN thin films were performed by energy dispersive X-ray spectroscopy (EDS). It was found that the deposition rate of the films increased with decreasing the nitrogen partial pressure ratio. The changes in crystal structures and morphological related with nitrogen partial pressure ratio were systematically investigated and discussed in this paper.

Effect of the nitrogen-argon gas mixtures on the superconductivity properties of reactively sputtered molybdenum nitride thin films

We report on the superconducting properties of nanocrystalline molybdenum nitride thin films grown by reactive DC sputtering at room temperature with a N2:Ar mixture. Thin films grown using 5% N2 concentration display Tc = 8 K, which is gradually reduced to 5.8 K for 30% N2 concentration, producing changes in nitrogen stoichiometry of the samples from Mo2N to Mo2N1+x (0 ≤ x < 0.4). The Tc is abruptly reduced and disappears for N2 concentration between 30% and 40%, which can be attributed to an increment in the disorder due to phase coexistence between cubic γ-Mo2N and non-superconducting amorphous MoN (dominant for N2 concentration >40%).

Microstructure of reactive magnetron sputtered S-phase coatings with a diffusion sub-layer

The main objective of the work was to investigate the microstructure of S-phase coatings obtained by reactive magnetron sputtering at different temperatures and with various nitrogen concentrations in the working atmosphere. Particular attention was paid to the formation of a diffusion sub-layer in the austenitic substrate. The coatings were deposited on austenitic stainless steel substrates in an argon–nitrogen gas mixture. Three different nitrogen concentrations in the working gas were used in the experiments (15, 33 and 50 vol.%), and five substrate temperatures (200, 250, 300, 350 and 400 °C). The phase composition was evaluated using X-ray diffraction (XRD). X-ray microanalysis (WDS) and glow discharge emission spectroscopy (GDOES) techniques were used to study the nitrogen content and distribution in the coatings. The microstructure was investigated using a scanning electron microscope (SEM). Formation of the S-phase diffusion sub-layers was observed in the atmospheres containing 50 and 33 vol.% N2 respectively at temperatures of 300 and 350 °C or higher. Nitrogen diffusion into the substrate also occurred with the 15 vol% N2 atmosphere at 350 °C or higher although no supersaturated solution was formed in these conditions.

Influence of nitrogen gas flow on the hardness and the tribological properties of a TiAlBN coating deposited by using a magnetron sputtering process

With a view to improving the mechanical properties of coatings applied in the field of cutting tools and machine parts, the TiAlBN coatings were deposited by using direction-current (dc) magnetron sputtering with the various contents of nitrogen gas in an argon-nitrogen gas mixture. The structural characteristics of the coatings were determined by using X-ray diffraction, the friction coefficient, and the hardness and elastic modulus of the coatings were investigated by using a tribometer and nano-indentation. The surface morphologies and the roughnesses of the coatings were analyzed by using field emission scaning electron microscopy (FESEM) and atomic force microscopy (AFM). Additionally, the effects of nitrogen gas flow on the properties of the TiAlBN coatings were investigated. The structural characterization results revealed a typical face-centered cubic TiN structure with (111), (220), and (222) diffraction peaks. The strongest intensity in the (111) orientation was obtained for the coating prepared at a nitrogen gas flow of 4 sccm. For this kind of samples were obtained the highest values of the hardness and the stability, a low friction coefficient, and a smooth surface.

Ionization of atoms and molecules in a strong two-color field

SynopsisWe experimentally investigated the asymmetry of photo-ion and photoelectron momentum spectra of argon and nitrogen by ionizing an argon-nitrogen gas mixture in a strong two-color (400 nm + 800 nm) laser field. By changing the time delay between the 400 nm laser pulse and the 800 nm pulse, the fan-like stripes in low-energy electron momentum shift from negative momentum to positive for both argon and nitrogen. A clear difference of asymmetric electron emission between Ar and N2 is observed.

Кінетика плазмохімічних реакцій утворення атомів азоту в жевріючому розряді в суміші азот–аргон

Кінетика плазмохімічних реакцій утворення атомів азоту в жевріючому розряді в суміші азот–аргон

Argon metastable and resonant densities in a low-pressure Ar–N2 inductively coupled plasma

Argon metastable (3P2 and 3P0) and resonant (3P1 and 1P1) atom densities have been measured in a low-pressure (1–20 mTorr) inductively coupled plasma generated in argon–nitrogen gas mixtures with nitrogen contents ranging from 0 to 90% using optical absorption spectroscopy techniques. A significant decrease of the metastable density is found for increasing nitrogen contents, more pronounced as the pressure is increased. As for the resonant atoms, their behaviour differs from that of metastable atoms, which results from the growing influence of radiation trapping with pressure. A simplified model accounting for several Ar metastable population/depopulation mechanisms (electron excitation/ionization, diffusion and excitation transfer from Ar metastable to nitrogen molecules) has been used to interpret these results. It shows that excitation transfer reactions from Ar metastable atoms to nitrogen become the main depopulation process, especially for large nitrogen contents and pressures above 10 mTorr.

Hard nanocrystalline Zr–B–C–N films with high electrical conductivity prepared by pulsed magnetron sputtering

Zr–B–C–N films were deposited on silicon and glass substrates using pulsed magnetron co-sputtering of a single B4C–Zr target (at 15% or 45% of zirconium in the target erosion area) in nitrogen–argon gas mixtures. A planar unbalanced magnetron was driven by a pulsed dc power supply operating at a repetition frequency of 10kHz with a fixed 85% duty cycle. The total pressure was 0.5Pa and the substrate temperature was adjusted to 450°C during the depositions on the substrates at a floating potential. High-quality defect-free films, 3.5 to 4.1μm thick, with smooth surfaces (the average roughness Ra≤4nm) and good adhesion to substrates at low compressive stresses (less than 0.9GPa) were produced. Hard (37GPa) nanocolumnar ZrB2-type films of the Zr25B57C14N3 composition (in at.% without 1at.% of hydrogen) with a very low compressive stress (0.4GPa), high electrical conductivity (electrical resistivity of 2.3×10−6Ωm) and high oxidation resistance in air up to 650°C were prepared in pure argon at a 15% Zr fraction in the target erosion area. Hard (37GPa) nanocomposite Zr41B30C8N20 films with a low compressive stress (0.6GPa), even higher electrical conductivity (electrical resistivity of 1.7×10−6Ωm) and high oxidation resistance in air up to 550°C were deposited in a 5% N2+95% Ar gas mixture at a 45% Zr fraction in the target erosion area. Increasing the N2 fraction (>5%) in the gas mixture resulted in a significant decrease of the film hardness and in a rapid rise in their electrical resistivity and oxidation resistance in air at elevated temperatures due to a growing volume fraction of an amorphous phase with a high content of nitrogen (up to 52at.%) in the materials.