Reactive Magnetron Sputtering Research Articles

Influence of aluminum addition on structure, hardness, and oxidation resistance of Ta1−xAlxN thin films

Ta1−xAlxN thin films with 5, 15, and 40 at.% Al addition were co‐deposited by reactive magnetron sputtering and characterized by Rutherford backscattering spectroscopy (RBS), grazing angle X‐ray diffraction (GAXRD), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nanohardness, and oxidation tests. GAXRD and XPS analyses showed, regardless of the % Al added, the non‐existence of ternary nitride Ta1−xAlxN, but always as individual binary nitrides, TaN and AlN. Sample TaAlN_15 obtained the highest hardness and H3/E2 values, possibly due to the AlN grains presence, which were efficient in distorting the TaN lattice. All samples failed oxidation tests at 873 K, showing that the Al addition was not efficient in improving this property for tantalum aluminum nitride thin films.

Effect of substrate temperature and position on properties of Cu3N thin films deposited by reactive radio frequency magnetron sputtering

Copper nitride (Cu3N) thin films were deposited on soda lime glass (SLG) substrates by reactive radio frequency (RF) magnetron sputtering using a pure Cu target in the presence of argon and nitrogen. The structural, optical, and electrical properties of the Cu3N films were investigated systematically on substrate temperature and position, demonstrating that both parameters strongly influence the properties of Cu3N thin films. XRD patterns revealed the formation of the Cu3N phase at all substrate temperatures and positions. The transmittance of the Cu3N thin films was over 80 % in the transparent region and the band gap for Cu3N was determined to 1.7–1.9 eV with a very high absorption coefficient above 104 cm−1. The n-type conductivity was observed in every Cu3N film but the resistivity varied considerably with both substrate temperature and position. The promising physical properties of Cu3N thin films suggest their potential application in optoelectronic devices such as thin film solar cells.

Optical and electrophysical properties of nitride TiAlSiN and carbonitride TiAlSiCN coatings: influence of reactive magnetron deposition regimes

The development of thin-film thermal control coatings for small spacecraft is relevant. Coatings based on titanium nitride are capable of functioning in unfavorable conditions of near and deep space, due to their high resistance to the irradiation by high-energy particles. Using the reactive magnetron sputtering method, the nanostructured TiAlSiN and TiAlSiCN coatings were formed on the substrates of silicon oxide (SiO2), glass-ceramic CT-1 and single-crystalline silicon (Si(100)). A study of the electrophysical and optical properties of the formed coatings was carried out. The deposited coatings demonstrate a good reflectivity in the infrared range of spectrum (700–2000 nm), what is important for reducing the overheating of the spacecraft (SC) under the influence of the direct sunlight. In the visible range of spectrum (400–700 nm), a low level of total Rtotal reflection is observed. This is promising for satellites designed to observe the Earth’s surface. The values of solar absorption coefficients αs, emissivity coefficients ε0, ratios αs/ε0, as well as the equilibrium temperature Tр for the samples under study were obtained. The values of resistivity ρ and surface resistance R□, electron concentration N and electron mobility μ were determined. It has been discovered that TiAlSiN, TiAlSiCN films are electrically conductive: ρTiAlSiN = (92÷4260) ∙ 10–7 Ω ∙ m, ρTiAlSiCN = (51÷2360) ∙ 10–7 Ω ∙ m. It has been found that adding carbon to the coating composition reduces the resistance. The obtained nanostructured coatings of TiAlSiN nitride and TiAlSiCN carbonitride can be used as temperature control coatings for small spacecrafts.

High performance symmetric supercapacitors based on Au incorporated CrN thin films fabricated by reactive magnetron sputtering

Recently, transition metal nitrides are being investigated extensively as potential supercapacitor material. In the present study, Au incorporated CrN (Au_CrN) thin films have been synthesized using reactive magnetron co-sputtering technique for application as supercapacitor electrode material. Films have been prepared at different Ar to N2 flow rates keeping total deposition pressure constant to achieve the required structural phase in the sample. Electrochemical properties of the deposited materials have been investigated with a three-electrode system in 0.5 M H2SO4 aqueous electrolyte. The CrN thin film deposited under 3:1 Ar: N2 partial pressure or flow rate ratio shows the highest specific capacitance. Upon Au incorporation, the film shows an areal capacitance of 56.8 mFcm−2 at 1.0 mAcm−2discharge current density which is an almost nine-fold enhancement in specific capacitance value compared to pristine CrN sample. Symmetric supercapacitors have also been developed by sandwiching two identical Au_CrN thin film electrodes, which have found to deliver excellent specific capacitance of 86.03 mFcm−2at 1.0 mAcm−2 discharge current density with no decline in capacitance value till 20,000 cycles. Furthermore, it can deliver a high energy density of 52.02mWhcm−2and a power density of 0.12mWcm−2. The electrochemical properties of the supercapacitors fabricated with the Au_CrN thin film electrodes are found to be better than most of the results reported so far in the literature with CrN electrodes. Results of the present study clearly demonstrate that these Au enhanced CrN films prepared by easily scalable and highly reproducible magnetron sputtering technique have great potential as a high capacitance supercapacitor electrode material.

Reaction of hydrogen peroxide with amorphous Ti–O surfaces

Amorphous Ti–O thin films were synthesized by reactive magnetron sputtering and their affinity to H2O2 was studied electrochemically. They exhibit a pronounced affinity to H2O2, with TiO0.6 outperforming TiO1.5 and TiO2. Cathodic currents in the range of −211 μA/cm2 suggest that TiO0.6 is highly electroactive to H2O2. Molecular dynamics simulations based on density functional theory revealed rapid dissociation of H2O2 into OH on Ti–O surfaces, leading to diffusion of OH, facilitating both oxidation and reduction processes. These OH groups predominantly dock onto bridge and atop sites, oxidizing the surfaces. Notably, stronger interactions observed for lower oxidation states give rise to higher cathodic currents. Additionally, the ability of amorphous Ti–O thin films to generate free H atoms implies a possible reduction mechanism, likely leading to the desorption of H2O. Hence, amorphous TiO0.6 is more suitable for detection and monitoring of H2O2 than higher oxidation states in their crystalline forms, e.g., rutile TiO2, known as a benchmark for such applications.

The effect of RF sputtering power on structural, nanomechanical and tribological properties of single layered TaN coatings

Single-layered TaN thin coatings were deposited on Ti6Al7Nb alloy substrates using reactive radiofrequency magnetron sputtering, with variations in target power. To assess the crystalline structure, chemical composition, and surface topography of these coatings, Grazing Incidence x-ray Diffraction (GIXRD), Energy Dispersive Spectroscopy (EDS), and Scanning Probe Microscopy (SPM) were employed, respectively. The study revealed that deposition power impacts the structure and composition of TaN coatings. Further analysis using x-ray Photoelectron Spectroscopy (XPS) indicated that the TaN coatings predominantly consisted of Ta and N, with trace amounts of oxygen (O 1s). Additionally, nanomechanical testing was conducted to evaluate hardness (H), modulus (E), and scratch properties. Results suggested that multiphase hex-TaN coatings exhibited superior H, E, and scratch properties compared to other cubic-structured TaN coatings. Friction and wear properties against steel balls under dry sliding conditions were determined using a ball-on-disk nanotribometer. The findings showed that mix-phase TaN coating exhibited a minimum coefficient of friction of 0.054 and a wear rate of 2.14 × 10−6 mm3/N.m. Abrasion, ploughing and oxidation were identified as the primary wear mechanism responsible for the wear of the TaN coatings.

High-temperature protection performance of Mg-doped Al2O3 protective layers on the thin film thermocouples

Mg-doped Al2O3 protective layers were deposited on Pt–PtRh10 (S-type) thin film thermocouples (TFTCs) by reactive magnetron sputtering. The changes in the composition, microstructure, and element distribution of the Mg-doped Al2O3 films before and after annealing at 1200 °C for 3 h were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The results indicate that incorporating MgO into Al2O3 as an enhancement phase not only inhibits the crystallization and phase transformation of Al2O3 but also promotes the formation of MgAl2O4, sequentially further enhancing the material's high-temperature protective properties. The thermoelectric properties of S-type TFTCs with 1.6 μm thick Al2O3 and Mg-doped Al2O3 protective layers were explored, respectively. The results of static calibration at high temperatures demonstrate that the TFTCs with the Mg-doped Al2O3 protective layer can operate at 1148 °C for over 96 h and at 1480 °C for a brief period. Following 4 calibration cycles, compared to the TFTCs with the Al2O3 protective layer, the average Seebeck coefficients of the TFTCs with the Mg-doped Al2O3 protective layer exhibit a slower decline rate, and its drift rate during the 4th cycle is merely 3.28 °C/h. The TFTCs featuring Mg-doped Al2O3 protective layers demonstrate extended lifetimes, superior high-temperature stability, and enhanced reliability when contrasted with those utilizing undoped Al2O3 protective layers. These attributes offer valuable insights into the progression of TFTC technology.

The electrical properties of nitrogen-doped vanadium dioxide thin films grown by magnetron sputtering

Abstract Vanadium dioxide (VO2) undergoes a reversible semiconductor-metal phase transition near 68°C, and the optical and electrical properties could be changed in femtoseconds. These unique characteristics meet the electro-optic switch applications. In this work, to improve the intrinsic characteristics of VO2, a series of nitrogen-doped vanadium dioxide thin films were prepared by reactive magnetron sputtering. Moreover, the effects of different nitrogen flow rates on the microstructure, surface morphology, electrical properties and phase transition properties of the samples were investigated. The samples are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), four-point probe system, and Hall effect et al. Sheet resistance variation at room temperature and high temperatures indicates remarkable semiconductor-metal transition characteristics. According to results of Hall effect measurement, when nitrogen flow rate is less than 1 sccm, the samples exhibits p-type semiconductor characteristics. However, while nitrogen flow rate reaches 1 sccm, n-type semiconductor characteristics appear. What’s more, Carrier mobility reaches a maximum at a nitrogen to oxygen flow ratio of 0.3. The results reveal that the samples have a great potential on electro-optic switching applications.

Fabrication of a hot mirror using ITO-free electrochromic films

In this study, WO3/Ag/W/WO3 (WAWW) films were deposited at room temperature on a B270 glass substrate from W and Ag targets using a radiofrequency magnetron reactive sputtering system. The influence of the thin tungsten interlayer on the electrical and optical properties of the WAWW layer structure was investigated through ellipsometry, a four-point probe and a spectrophotometer. It was determined that the thin tungsten interlayer effectively prevented the oxidation of the silver film. The WAWW film had a dielectric-metal-dielectric (DMD) layered structure with good electrical conductivity and high visible transmittance. The tungsten layer was no more than 2-nm thick. The sheet resistance and luminous transmittance of the WO3(29.5 nm)/Ag(14.2 nm)/W(2 nm)/WO3(68.6 nm) film were 4.64 Ω/sq and 65.4 %, respectively. Based on the WAWW four-layer structure, stacked WO3(29.5 nm)/Ag(14.2 nm)/W(2 nm)/WO3(68.6 nm)/Ag(16.9 nm)/W(2 nm)/WO3(30.4 nm) seven-layer structures deposited on B270 glass substrates were used for both ITO-free electrochromic and hot mirror applications. The visible (400–700 nm) and NIR (700–1200 nm) transmittance values of the bleached WAWW seven-layer structure were 71.5 % and 9.9 %, respectively. The visible transmittance of the colored WAWW seven-layer structure was 23.6 %. Finally, the bi-layer WAWW films were used to obtain an ITO-free WAWW seven-layer structure with a good electrochromic and optical performance.

The synergistic effect of Ta-doping and antireflective TaOx layer on the thermochromic VO2 thin films for smart windows

Current efforts to promote the use of VO2 materials as a promising candidate for thermochromic smart windows continue to be hindered by the low luminous transmittance (Tlum), the limited solar modulation ability (ΔTsol), the high phase transition temperature (Tt, ∼68 °C) and the wide thermal hysteresis (ΔT). The present work addresses these issues by fabricating an antireflective TaOx layer on the Ta-doped VO2 (i.e., VO2(Ta)) thin films. The VO2(4.35 at% Ta) thin films with low Tt of 29.87 °C and narrowed ΔT of almost zero were grown on glass substrates by magnetron sputtering at room temperature followed by rapid thermal annealing. However, the VO2(Ta) thin films show slightly enhanced Tlum of 38.31 % compared with undoped VO2 films (35.46 %) and decreased the ΔTsol by 1.83 %. The thermochromic properties are further enhanced by depositing the antireflective TaOx layer onto the VO2(Ta) thin film by reactive magnetron sputtering, which significantly increases the Tlum from 38.31 % to 48.58 %, marginally decreases the ΔTsol from 4.44 % to 4.12 %, and maintain the Tt and ΔT constant. These results verify the possibility of developing VO2 films with simultaneously increased optical transmittance, decreased Tt to suitable values, and extremely narrow ΔT by using the synergistic effect of element doping and constructing an antireflective layer.

Synthesis of epitaxial LuN films

Epitaxy of rare-earth nitride films are crucial for studying their physical properties and offer significant potential for applications in spintronics and optoelectronics. However, synthesizing single-crystalline LuN presents significant challenges, leading to a limited understanding of its properties. In this study, we successfully achieved the epitaxial growth of (001)-oriented LuN films on YAlO3 (110) substrates by reactive magnetron sputtering epitaxy. Electrical transport measurement at low temperatures reveals that the LuN film exhibits semiconducting behavior between 300 K and 2 K, with an activation energy of approximately 0.01 eV. Notably, negative magnetoresistance was observed below 12 K, which can result from the defects and magnetic impurities in LuN films. Our results uncover the electronic and magnetic properties of epitaxial LuN films.

Microstructures and tribological properties of MoS2/Mo2N multilayer gradient films deposited by reactive magnetron sputtering

In order to compare the microstructures and tribological properties of films, pure Mo2N, pure MoS2, 3-layer and 13-layer MoS2/Mo2N gradient films were deposited by reactive magnetron sputtering. The crystalline structure, surface and cross-section morphologies, 3D surface topography, binding energy, hardness and tribological properties of films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atom force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), nanoindenter, and wear tester, respectively. The results indicate that the preferred orientation of MoS2 in gradient films has changed. The surface and cross-section structures of gradient films become denser with increasing the number of gradient layers. Average surface roughness (Ra) of pure MoS2 film is the highest, and Ra of 13-layer film is the lowest. The binding energy of MoS2 in the composite layer of gradient film has changed. The hardness of gradient film is higher than that of MoS2 and lower than that of Mo2N. The wear resistance of gradient films is much better than that of pure MoS2, and this phenomenon is more obvious under high load conditions. The improvement in the wear resistance of gradient films is attributed to the increase of dense, hardness, H/E and H3/E2. In the initial stage of friction, the 3-layer gradient film can maintain low friction coefficient (≤0.15), which is attributed to the thick MoS2 surface layer. The wear resistance of 13-layer is much better than that of 3-layer gradient film, because it has higher hardness, higher H/E and H3/E2 than 3-layer gradient film.

Effect of sputtering power and oxygen partial pressure on structural and opto-electronic properties of Al-doped ZnO transparent conducting oxides

This paper presents the results of electrical, optical and structural properties, along with studies of the surface morphology and cross sections of aluminium-zinc oxide (AZO) thin films. The thin films were fabricated by reactive magnetron sputtering using the two-element Zn-Al disk. The properties of the thin films prepared using different sputtering power densities and different oxygen partial pressures in the working chamber were discussed. To control the partial pressure of oxygen, a characteristic parameter of the magnetron power supply, called the circulating power, was used. The best properties of prepared AZO thin film as a transparent oxide conducting thin film were found for the film prepared using the ratio of circulating to effective power equal to 0.5. For that thin film, the electron concentration of about 6·1020 and the band gap properties (bandgap width equal to 3.14 eV, work function equal to 3.75 eV) were determined.

Technologia reaktywnego rozpylania magnetronowego do otrzymywania azotków III

In the present work is studied synthesis of galium nitride (GaN) and aluminum nitride (AlN) by DC Reactive Magnetron Sputtering technology. As a sputtering target was used high purity (99.9999%) Gallium and Aluminum materials and as a reagent gas was used high purity (99.9999%) Nitrogen. Magnetron sputtering system with strong magnets (1450 mT) allows to make plasma at a low preasure 3 × 10-2 Pa and deposition process was carried out at high vacuum conditions. Deposited layers of GaN and AlN on the sappire substrate was analysed by X-ray diffraction (XRD) and revealed the crystalline nature highly oriented with the (0002) for both nitrides. For chemical composition was measured X-ray Photoelectron Spectroscopy (XPS) and it was found out the ratios of Ga:N and Al:N to be 1.07 and 1.04 respectively. For surface analysis was made Scanning Electron Microscopy (SEM). Optic transmission spectra showed band gaps to be 3.43 eV and 6.13 eV for GaN and AlN respectively.

NbTiN SQUID-on-tip fabricated by self-aligned deposition using reactive DC magnetron sputtering

We fabricate superconducting quantum interference devices (SQUIDs) made of niobium-titanium nitride (NbTiN) thin films on the apex of sharp quartz capillaries. By incorporating reactive DC magnetron sputtering into the self-aligned deposition process for the SQUID-on-tip (SOT) fabrication, we produce NbTiN SOT devices with an effective diameter of ∼100 nm. The ø110 nm device has a superconducting transition temperature of 13.2 K, magnetic flux noise down to 0.7 μΦ0/Hz0.5 (4 K), and operating temperatures of 1.8–10 K. The developed technique enables the synthesis of nitride and other superconductors, thereby expanding the range of materials available for SOT devices.

Memrystor na bazie HfO2-HfOx z warstwami aktywnymi o różnych rozmiarach

Memristore parameters are strongly depend on the size of active layers. In this paper is reported the outcomes of memristore created with different size active layers. There are considered 1μ, 5μ and 10μ diameter separated devices in the form of crossbar with HfO2 + HfOx active layer and tungsten top contact, titanium nitride botton contact and aluminum wiring contact. As substrate was used sapphire and active layers of memristore was deposited by reactive magnetron sputtering technology. With photolithography exposure system by new pothomask has been done 1μ, 5μ and 10μ diameter lithography for formation active layers and all contacts. Leakage currents dropped to 0.01mA, increased cicles of histeresis of I-V curves and dramatically increased Roff /Ron ratio to be 100000.

The influence of low nitrogen doping on bacterial adhesion of sputtered a-C:H coatings

Heavily dependent on both surface and bacteria characteristics, multiple and complex parameters control bacterial adhesion to any biomaterial surface. That's why there are so many contradictory results regarding the antibacterial and adhesion inhibition properties of Diamond-Like Carbon (DLC) protective coatings, despite the well-established biocompatibility of this very broad group of materials. Aiming at Orthodontics, this study reports the modification of hydrogenated amorphous carbon coatings (a-C:H), by nitrogen incorporation upon reactive magnetron sputtering. The effect of low N content up to 10 at.% on the microstructure and bacterial adhesion was studied. Despite the progressive graphitization upon doping, the surface roughness was not significantly influenced and the water contact angles remained above 70°. The adhesion of three bacterial strains of Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa was evaluated. The median colony forming units was lower on the a-C:H and a-C:H:N coatings in comparison to the bare AISI 316L medical grade stainless steel surface, regardless the bacterial strain. The best bacterial adhesion inhibition capacity was achieved for N doping of 6 at.%, without using any antibacterial agents.

Effects of substrate bias voltage on conductivity and internal stress of TiN films

In order to make the service life of microelectronic devices longer, titanium nitride electrode films need to meet the requirements of high electrical conductivity and low internal stress. In this paper, the effect of substrate bias voltage on the properties of titanium nitride films prepared by direct current (DC) reactive magnetron sputtering was studied systematically. The changes of titanium nitride films properties were investigated in detail from the aspects of resistivity, growth rate, crystal orientation, roughness and internal stress. The results show that the introduction of substrate bias voltage is conducive to the formation of dense titanium nitride films. Considering that the resistivity and internal stress of titanium nitride film vary with substrate bias voltage, the film deposited at substrate bias voltage of -100 V is selected as the electrode film material with the best performance (resistivity of 47.5 μΩ·cm, roughness of 1.1 nm and internal stress of -5.6 GPa).

Influence of the elemental composition on the structural and mechanical characteristics of entropy-stabilized HfZrCeYMgAlO thin films prepared by reactive magnetron sputtering

Entropic stabilization of the crystal structure of solids was demonstrated for various systems, starting with metals and continuing with oxides, nitrides, borides, and more complex structures. The influence of additional thermodynamic driving forces sometimes allow to stabilize the material in a crystalline configuration that is unusual for it. In this paper, we focused on the HfZrCeYMgO system, which has shown excellent mechanical properties and a stable crystal structure. We added different concentrations of aluminum oxide, but found that even in significant quantities, it was embedded in the lattice without separating into separate phases. At the same time, we found that the addition of aluminum significantly increases the crystallinity of the coating as well as its mechanical characteristics. We associate the increase in coating crystallinity with a consistent increase in the entropy of mixing in the HfZrCeYMgAlO system.

Oxidation Performance of Nano-Layered (AlTiZrHfTa)Nx/SiNx Coatings Deposited by Reactive Magnetron Sputtering.

This work uses the direct current magnetron sputtering (DCMS) of equi-atomic (AlTiZrHfTa) and Si targets in dynamic sweep mode to deposit nano-layered (AlTiZrHfTa)Nx/SiNx refractory high-entropy coatings (RHECs). Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are used to investigate the effect of Si addition on the oxidation behavior of the nano-layered coatings. The Si-free nitride coating exhibits FCC structure and columnar morphology, while the Si-doped nitride coatings present a FCC (AlTiZrHfTa)N/amorphous-SiNx nano-layered architecture. The hardness decreases from 24.3 ± 1.0 GPa to 17.5 ± 1.0 GPa because of the nano-layered architecture, whilst Young's modulus reduces from 188.0 ± 1.0 GPa to roughly 162.4 ± 1.0 GPa. By increasing the thickness of the SiNx nano-layer, kp values decrease significantly from 3.36 × 10-8 g2 cm-4 h-1 to 6.06 × 10-9 g2 cm-4 h-1. The activation energy increases from 90.8 kJ·mol-1 for (AlTiZrHfTa)Nx nitride coating to 126.52 kJ·mol-1 for the (AlTiZrHfTa)Nx/SiNx nano-layered coating. The formation of a FCC (AlTiZrHfTa)-Nx/a-SiNx nano-layered architecture results in the improvement of the resistance to oxidation at high temperature.