Magnetron Sputtering Technology Research Articles

CMOS-Compatible Tellurium/Silicon Ultra-Fast Near-Infrared Photodetector.

High-quality photodetectors are always the main way to obtain external information, especially near-infrared sensors play an important role in remote sensing communication. However, due to the limitation of Silicon (Si) wide bandgap and the incompatibility of most near infrared photoelectric materials with traditional integrated circuits, the development of high performance and wide detection spectrum near infrared detectors suitable for miniaturization and integration is still facing many obstacles. Herein, the monolithic integration of large area tellurium optoelectronic functional units is realized by magnetron sputtering technology. Taking advantage of the type II heterojunction constructed by tellurium (Te) and silicon (Si), the photogenerated carriers are effectively separated, which prolongs the carrier lifetime and improves the photoresponse by several orders of magnitude. The tellurium/silicon (Te/Si) heterojunction photodetector demonstrates excellent detectivity and ultra-fast turn-on time. Importantly, an imaging array (20 × 20 pixels) based on the Te/Si heterojunction is demonstrated and high-contrast photoelectric imaging is realized. Because of the high contrast obtained by the Te/Si array, in comparison with the Si arrays, it significantly improve the efficiency and accuracy of the subsequent processing tasks when the electronic pictures are applied to artificial neural network (ANN) to simulate the artificial vision system.

Effects of intrinsic mechanical properties on the dynamic bonding strength of GLC films undergoing ball bearing contact fatigues

Wear-resistant films, which are widely applied to extend the service life of the gears and bearings, usually surfer from dynamic bonding fatigue failure induced by the Hertz-like contact. However, there is still lack of research on the influence of the main mechanical parameters of films on the dynamic bonding fatigue failure mechanism. In this work, graphite-like carbon (GLC) films with a low friction coefficient and different Ti doping ratios were deposited on the surface of stainless steel via direct current magnetron sputtering (DCMS) technology. The microstructure and mechanical properties of the films before and after vacuum annealing were investigated by SEM, Raman, and nanoindentation, and the dynamic bonding failure life of the films were evaluated by the ball-bearing-disc method with dynamic contact fatigue loads. The results revealed that the critical dynamic bonding strength exhibited a significant function dependence on the values of hardness-to-elastic modulus (H3/E2) parameters of the GLC films. The film failure mechanism showed a transition from the film/substrate interface spalling mode to the near-surface cohesion shear spalling mode with the increase of H3/E2.

Effect of Au Doping on ZnO Nanoporous Structure for H2S Gas Sensing

This research mainly constitutes the fabrication of semiconductor gas sensors using high Power pulse magnetron sputtering (HiPIMS) technology to deposit ZnO thin films. As a doping substance, different thicknesses of gold plating is deposited on the surface of ZnO thin films. Various thicknesses of gold used in the study are 3.3 nm, 6.6 nm, 10 nm, 13.3 nm and 16.6 nm. The structural properties of thin films were identified by X-ray- diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). EDS analysis conveyed that gold particles filled the pores of nanoporous ZnO structures, which increased the films surface area and enhancing the gas sensing response. Various concentrations of H2S gas is used to test the gas sensing properties and the results proved the Au doped ZnO thin film sensor has enhanced sensing than the pure ZnO thin film sensor. 10 nm thickness doped Au has prime sensing properties with the operating temperature of 300 °C. Other sensing properties such as repeatability, selectivity and effect of humidity are tested and presented the data which shows the Au doping ZnO superiority over pure ZnO thin films.

Research on the surface characterization, corrosion and bioactivity of nano-featured tantalum coating on selective electron beam melted Ti6Al4V alloy

A nano-featured tantalum coatings with an average thickness of 800 nm and grain size of 50 nm were successfully prepared by Selective Electron Beam Melted (SEBM) Ti6Al4V substrates by DC magnetron sputtering technology. The details of the physicochemical properties, corrosion resistance and in vitro biocompatibility of the coating were systematically investigated. Elastic modulus of the nano tantalum coatings was around 123.8 GPa and the hardness was 8.08 GPa. Compared with uncoated Ti6Al4V matrix, the corrosion potential of the Ta-Ti64 samples was positively shifted and the corrosion current density decreased from 2.07 × 10−7 to 2.85 × 10−8 A·cm−2 (0.1 mV/s). EIS and PDP results show that the coating enhances the humoral corrosion resistance of Ti6Al4V, which can provide active protection for the substrate to prevent the release of toxic ions caused by long-term corrosion. The mouse osteoblast cell line (MC3T3-E1) is applied in this study for biological evaluation. The optical density at 450 nm results showed that the cell proliferation rate of tantalum coated surface was faster than that of Ti6Al4V sheet and pure tantalum sheet. The 5-day cell adhesion density is 1.26 and 1.32 times higher than uncoated Ti6Al4V and pure tantalum respectively. The nano-structured Ta layer significantly improved the initial adhesion of MC3T3-E1 cells and promoted cell proliferation. The corrosion resistance and biocompatibility of Ta coating are not only better than titanium matrix, but also better than pure tantalum. The results prove that tantalum coating is an effective method to modify titanium alloy and holds a great potential value on 3D printed personalized implants application.

Investigation of magnetization reversal and domain structures in perpendicular synthetic antiferromagnets by first-order reversal curves and magneto-optical Kerr effect

Perpendicular synthetic-antiferromagnet (p-SAF) has broad applications in spin-transfer-torque magnetic random access memory and magnetic sensors. In this study, the p-SAF films consisting of (Co/Ni)3]/Ir(t Ir)/[(Ni/Co)3 are fabricated by magnetron sputtering technology. We study the domain structure and switching field distribution in p-SAF by changing the thickness of the infrared space layer. The strongest exchange coupling field (H ex) is observed when the thickness of Ir layer (t Ir) is 0.7 nm and becoming weak according to the Ruderman–Kittel–Kasuya–Yosida-type coupling at 1.05 nm, 2.1 nm, 4.55 nm, and 4.9 nm in sequence. Furthermore, the domain switching process between the upper Co/Ni stack and the bottom Co/Ni stack is different because of the antiferromagnet coupling. Compared with ferromagnet coupling films, the antiferromagnet samples possess three irreversible reversal regions in the first-order reversal curve distribution. With t Ir increasing, these irreversible reversal regions become denser and smaller. The results from this study will help us understand the details of the magnetization reversal process in the p-SAF.

Ultrafast nonlinear optical properties of Ag/WTe2 composite films

WTe2 thin films and Ag/WTe2 composite films were successfully prepared by magnetron sputtering technology. The nonlinear absorption (NLA) characterization of the Ag/WTe2 composite system at 532 nm was also investigated by the ps Z-scan technique. The results show that both WTe2 films and Ag/WTe2 composite films exhibit saturable absorption (SA) effect and self-dispersion phenomenon. In addition, the nonlinear absorption performance of the composite films are significantly enhanced compared to that of a single WTe2. With the increase of Ag sputtering power, their third-order nonlinear absorption coefficients β increase by one order of magnitude, indicating that Ag enhances the nonlinear absorption performance of Ag/WTe2 composite films. This study provides a new idea for the application of Ag/WTe2 composite films in optoelectronic devices.

Lightweight diamond/Cu interface tuning for outstanding heat conduction

AbstractWith rapid developments in the field of very large‐scale integrated circuits, heat dissipation has emerged as a significant factor that restricts the high‐density integration of chips. Due to their high thermal conductivity and low thermal expansion coefficient, diamond/Cu composites have attracted considerable attention as a promising thermal management material. In this study, a surface tungsten carbide gradient layer coating of diamond particles has been realized using comprehensive magnetron sputtering technology and a heat treatment process. Diamond/Cu composites were prepared using high‐temperature and high‐pressure technology. The results show that, by adjusting the heat treatment process, tungsten carbide and di‐tungsten carbide are generated by an in situ reaction at the tungsten–diamond interface, and W–WC–W2C gradient layer‐coated diamond particles were obtained. The diamond/Cu composites were sintered by high‐temperature and high‐pressure technology, and the density of surface‐modified diamond/Cu composites was less than 4 g cm−3. The W–WC–W2C@diamond/Cu composites have a thermal diffusivity as high as 331 mm2 s−1, and their thermal expansion coefficient is as low as 1.76 × 10−6 K−1. The interface coherent structure of the gradient layer‐coated diamond/copper composite can effectively improve the interface heat transport efficiency.

High-entropy alloy: An alternative approach for high temperature microwave-infrared compatible stealth

To achieve microwave-infrared compatible stealth in high temperature conditions, high-entropy alloys (HEAs) thin films were deposited on Al2O3 matrix by magnetron sputtering technology. Films were annealed to investigate thermal stability at 500 °C, 600 °C and 700 °C, respectively. Results from X-ray diffract meter (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), and Fourier transform infrared spectrometer (FTIR) suggested that high-entropy alloy (HEA) film was seriously oxidized when the annealed temperature reached 700 °C for 6 h, causing a significant decrease of infrared reflectivity. Conversely, HEA films showed low infrared emissivity of 0.09 at 600 °C. Additionally, the films possessed excellent thermal stability at 500 °C for 20 h with low infrared emissivity of 0.11. Finally, a simple metamaterial design utilizing HEA films was proposed for infrared-microwave compatible stealth. With the ability of incorporating excellent thermal stability and durable high temperature stealth performance, the study shows great potential of introducing HEAs in the field of high temperature compatible stealth.

Enhancing the high-temperature energy storage performance of PEI dielectric film through deposition of high-dielectric PZT coating layer

Dielectric film capacitors are a highly ubiquitous and indispensable electronic component, serving a crucial role in a wide array of electronic devices and power systems. Despite their extensive use, polymer film capacitors are often hampered by the conduction loss that ensues when they are subjected to high electric fields and temperatures. As a result, this leads to a significant reduction in energy density and charge-discharge efficiency. To solve this issue, magnetron sputtering technology was used to create a sandwich structure made of polyetherimide (PEI) thin films with lead zirconate titanate (PZT) inorganic layers coated on both sides. This remarkable innovation has successfully introduced the high dielectric PZT layer in the PEI film/metal electrode, substantially augmenting the barrier height at the dielectric/polymer interface. This has also resulted in a marked decrease in conduction loss, as conclusively validated by the experimental findings. At 150 °C and with charge-discharge efficiency above 90%, the maximum discharged energy density is 3.26 J/cm3, which is increased by 263% compared to the pristine PEI films (1.24 J/cm3 at 290 MV/m and 150 °C). This study designed a unique inorganic barrier layer of PZT to increase the energy storage capability of polymer dielectric films in high-temperature environments.

Giant Magnetoimpedance Effect of Multilayered Thin Film Meanders Formed on Flexible Substrates.

The giant magnetoimpedance effect of multilayered thin films under stress has great application prospects in magnetic sensing, but related studies are rarely reported. Therefore, the giant magnetoimpedance effects in multilayered thin film meanders under different stresses were thoroughly investigated. Firstly, multilayered FeNi/Cu/FeNi thin film meanders with the same thickness were manufactured on polyimide (PI) and polyester (PET) substrates by DC magnetron sputtering and MEMS technology. The characterization of meanders was analyzed by SEM, AFM, XRD, and VSM. The results show that multilayered thin film meanders on flexible substrates also have the advantages of good density, high crystallinity, and excellent soft magnetic properties. Then, we observed the giant magnetoimpedance effect under tensile and compressive stresses. The results show that the application of longitudinal compressive stress increases the transverse anisotropy and enhances the GMI effect of multilayered thin film meanders, while the application of longitudinal tensile stress yields the opposite result. The results provide novel solutions for the fabrication of more stable and flexible giant magnetoimpedance sensors, as well as for the development of stress sensors.

The effect of surface nucleation modulation on the mechanical and biocompatibility of metal-polymer biomaterials.

The deployment of hernia repair patches in laparoscopic procedures is gradually increasing. In this technology, however, understanding the new phases of titanium from the parent phase on polymer substrates is essential to control the microstructural transition and material properties. It remains a challenging area of condensed matter physics to predict the kinetic and thermodynamic properties of metals on polymer substrates from the molecular scale due to the lack of understanding of the properties of the metal-polymer interface. However, this paper revealed the mechanism of nucleation on polymer substrates and proposed for the first record a time-dependent regulatory mechanism for the polymer-titanium interface. The interconnection between polymer surface chain entanglement, nucleation and growth patterns, crystal structure and surface roughness were effectively unified. The secondary regulation of mechanical properties was accomplished simultaneously to satisfy the requirement of biocompatibility. Titaniumized polypropylene patches prepared by time-dependent magnetron sputtering technology demonstrated excellent interfacial mechanical properties and biocompatibility. In addition, modulation by low-temperature plasma metal deposition opened a new pathway for biomaterials. This paper provides a solid theoretical basis for the research of titanium nanofilms on medical polypropylene substrates and the medical industry of implantable biomaterials, which will be of great value in the future.

Refractory high-entropy alloys: A focused review of preparation methods and properties

• We reviewed the preparation methods of RHEAs, including metallurgical smelting, powder metallurgy, magnetron sputtering and additive manufacturing technology. • The microstructure and phase transformation process of RHEAs were analyzed. • The mechanical properties and main strengthening and toughening mechanisms of RHEAs, such as solid solution strengthening, precipitation strengthening and the transformation-induced plastic (TRIP) were discussed. • The properties of RHEAs, including high strength, oxidation resistance, corrosion resistance and wear resistance were reviewed. • We particularly focus on the generation of the ideal room temperature toughness of brittle BCC-structure RHEAs to achieve the combination of high strength and high toughness as engineering materials. In recent years, high-entropy alloys (HEAs) have become prominent metallic materials due to their unique design strategies and excellent mechanical properties. The HEAs-inherent high-entropy, lattice-distortion, sluggish-diffusion, and cocktail effects make HEAs maintain high strength, oxidation resistance, corrosion resistance, wear resistance, and other excellent comprehensive properties, showing stronger competitiveness relative to traditional alloys. Refractory high-entropy alloys (RHEAs) are considered as a new kind of high-temperature materials with great application prospects due to their excellent mechanical properties and have the potential to replace nickel-based superalloy as the next generation of high-temperature materials. We reviewed the research status and preparation methods of RHEAs in recent years, including the metallurgical smelting, powder metallurgy, magnetron sputtering, and additive manufacturing technologies. The microstructure and phase-transformation process of RHEAs were analyzed. The mechanical properties and main strengthening and toughening mechanisms of RHEAs, such as solid-solution strengthening, precipitation strengthening, and the transformation-induced plasticity (TRIP), were discussed, and the deformation mechanism of RHEAs was revealed. The properties of RHEAs, including high strength, oxidation resistance, corrosion and wear resistance were reviewed. RHEAs will meet the huge market demand in the engineering materials field, but there are still many challenges, such as the trade-off between high strength and high ductility, structural design, and performance optimization of RHEAs with brittle BCC structures. We believe that this combination of knowledge may shape the future of RHEAs and break through the mutually exclusive conundrum of high strength and high toughness for RHEAs.

A Comparative Investigation on the Microstructure and Thermal Resistance of W-Film Sensor Using dc Magnetron Sputtering and High-Power Pulsed Magnetron Sputtering

Traditional dc magnetron sputtering has a low ionization rate when preparing metallic thin films. With the development of thin film science and the market demand for thin film material applications, it is necessary to improve the density of magnetron-sputtered films. High-power pulsed magnetron sputtering (HiPIMS) technology is a physical vapor deposition technology with a high ionization rate and high energy. Therefore, in this work, HiPIMS was applied to prepare metallic tungsten films and compare the surface morphology and microstructure of metallic tungsten films deposited using HiPIMS and dc magnetron sputtering (dcMS) technology under different pulse lengths, as well as related thermal resistance performance, followed by annealing treatment for comparative analysis. We used AFM, SEM, XRD, and plasma characterization testing to comprehensively analyze the changes in the TCR value, stability, repeatability and other related performance of the metallic tungsten thin-film sensor deposited by the HiPIMS technology. It was determined that the thin film prepared by the HiPIMS method is denser, with fewer defects, and the film sensor was stable. The 400 °C annealed sample prepared using HiPIMS with a 100 μs pulse length reaches the largest recorded TCR values of 1.05 × 10−3 K−1. In addition, it shows better stability in repeated tests.

Fabrication and Optimization of Nafion as a Protective Membrane for TiN-Based pH Sensors.

In this study, a solid-state modified pH sensor with RF magnetron sputtering technology was developed. The sensor consists of an active electrode consisting of a titanium nitride (TiN) film with a protective membrane of Nafion and a reference glass electrode of Ag/AgCl. The sensitivity of the pH sensor was investigated. Results show a sensor with excellent characteristics: sensitivity of 58.6 mV/pH for pH values from 2 to 12, very short response time of approximately 12 s in neutral pH solutions, and stability of less than 0.9 mV in 10 min duration. Further improvement in the performance of the TiN sensor was studied by application of a Nafion protective membrane. Nafion improves the sensor sensitivity close to Nernstian by maintaining a linear response. This paves the way to implement TiN with Nafion protection to block any interference species during real time applications in biosensing and medical diagnostic pH sensors.

Wettability and corrosion resistance of zirconium nitride films obtained via reactive high-power impulse magnetron sputtering

One of the main problems in ships is corrosion, which reduces the lifetime usage of ship parts and increases maintenance costs. Ceramic coatings can contribute to solving this situation. Zirconium nitrides obtained by reactive unbalanced magnetron sputtering technology are largely reported as coatings with high corrosion resistance. The present study used high-power impulse magnetron sputtering in a reactive atmosphere (R-HiPIMS), varying the nitrogen amount. SEM, EDS, XRD, AFM, and contact angle measurements were used to assess the obtained coatings’ performance. Corrosion resistance was evaluated using electrochemical impedance spectroscopy (EIS) (up to 168 h exposure) and potentiodynamic polarization (PP) in NaCl (3.5% wt.—“artificial seawater”) solution. According to the results, cross section micrographs showed strong densification of ZrN films regardless of the nitrogen amount. Besides, nitrogen increases during deposition influenced the drop of applied peak power (Pp) to the target and, consequently, influenced other film properties, such as roughness, wettability, and corrosion resistance. PP and EIS tests demonstrate the protective behavior of films under artificial seawater exposure. The results prove that the implementation of HiPIMS technology to obtain ZrN films could contribute to increasing the corrosion resistance of coated ship metallic parts and, hence, help maritime transportation to reduce maintenance time and cost.

Advances in Preparation Technology of Tool Coatings

With the continuous development of modern industry and the difficult-to-machine materials gradually increases, the machining requirements of cutting tools continue to improve and the cutting environment is increasingly harsh. As the coating applies, the efficiency and precision of machining have been effectively improved. Coating on the tool surface can not only extend the service life of the cutting tool, greatly reduce the processing cost, but also reduce the environmental pollution in the process of processing. Excellent coating preparation technology is an important factor for its effective performance. According to different processing requirements, processing costs and processing environment, researchers have been working hard on the road of coating preparation technology. In this work, it summarizes the principle of physical vapor deposition, chemical vapor deposition and the corresponding advantages and disadvantages, and briefly introduces the pulsed DC magnetron sputtering, high power pulsed magnetron sputtering, arc ion plating and a variety of composite magnetron sputtering technologies.

Performance and structure of Ti-doped amorphous carbon/CrN/Ti multilayer coating deposited on 316L stainless steel for use as bipolar plate in proton exchange membrane fuel cell

In order to improve the corrosion resistance and conductivity of stainless steel bipolar plates, three-layer Ti-doped amorphous carbon/CrN/Ti films were deposited on 316L stainless steel used for bipolar plates in PEMFCs. Titanium as the doped element added into amorphous carbon. Magnetron sputtering technology was used to deposit the films and control the titanium doped content by different titanium target currents. The structure transformation law of Ti content in amorphous carbon coating was studied. The application principle of corrosion resistance and conductivity of bipolar plates during the transformation of the coating structure from amorphous carbon to carbide was analyzed. With increasing Ti-doped content, the sp2/sp3 ratio increased, and the amorphous carbon film gradually transformed to titanium carbide matrix film. Characterization of the electrochemical corrosion confirmed that the anti-corrosion property of the films was closely related to the Ti-C phase and sp2/sp3 ratio. Ti-doped amorphous carbon/CrN/Ti film, which is built at 1A Ti target current, has the best corrosion current density. The interfacial contact resistance (ICR) first decreased and then increased with increasing Ti content. When excessive doping of titanium atoms makes the coating become a TiC matrix, the corrosion resistance and ICR property of the coating worsen. The film’s state of chemical bonds after electrochemical corrosion was tested by XPS to study the ICR increase mechanism. The Ti-doped amorphous carbon/CrN/Ti multilayer film can be used as a modified coating of 316L stainless steel bipolar plates for PEMFCs.

Study of Microstructure Regulation and In Situ Tensile Performance of Ni-Al Films

In this paper, Ni-Al films were prepared using magnetron sputtering technology. The microstructure of the films and the relationship between the residual stress and the adhesion strength were studied. More importantly, the mechanical strength–ductility properties of Ni-Al films were evaluated by in situ tensile testing. The results showed that the film mainly consisted of Ni3Al phase and Ni-based solid solution at the low power of Al target. The phase transition occurred, and the NiAl phase appeared when the Al sputtering power was increased. The complex structure, with the coexistence of Ni-based solid solution, Ni3Al, and NiAl phases, possessed increased residual stress and reduced adhesion strength. Meanwhile, the crack was easily penetrated through the inside and outside of the film, falling off during in situ tensile testing. While the small residual stress and large adhesion strength were obtained, only Ni3Al and NiAl coexisted, and the film fell off with difficulty. When the Al sputtering power was 400 W, the film showed the largest adhesion strength and the smallest residual stress. The best comprehensive performance was achieved with a tensile strength of 854 MPa and a yield strength of 90 MPa. The Al content of the film was up to 23.03 at.%, which was beneficial to the application and performance improvement of the film in molten salt corrosion resistance.

Multifunctional nanofiber mat for high temperature flexible sensors based on electrospinning

The application environment and scenarios of flexible sensors are limited by the low temperature tolerance of the flexible substrate and the lack of protection of the sensitive layer surface. A flexible alumina-silicon oxide composite nanofiber mat (Al2SiO5) with high-temperature resistance is obtained based on electrospinning technique. The maximum tensile strength of the nanofiber mat reach 3.09 MPa and the maximum withstanding temperature exceeds 973 °C through parameter optimization. The patterned functional thin films are successfully prepared on the flexible Al2SiO5 nanofiber mat by using magnetron sputtering technology, vacuum vapor deposition technology and ink jet printing technology and other coating processes. Meanwhile, the process characteristics of the nanofiber mat prepared by electrospinning technique are fully utilized to realize flexible packaging of the high-temperature flexible sensors. Multifunctional nanofiber mats prepared based on electrospinning have great prospects for future applications in the field of flexible sensors.

Design and tribological performance of CrN/Mo2N/MoSx composite coating in wide temperature range inspired by oxidation kinetics principle

Inspired by oxidation kinetics principle, a series of CrN/Mo2N/MoSx composite coatings with different compositions were prepared by magnetron sputtering technology. Microstructure, chemical composition and mechanical were systematically investigated. The friction and wear behaviors of the CrN/Mo2N/MoSx coatings sliding against Al2O3 ceramic ball at 25–750 ℃ were also evaluated by a ball-on-disc tester (load: 2 N, frequency: 5 Hz, sliding distance: 5 mm). X-ray diffraction, transmission electron microscope and Raman spectroscopy were used to thoroughly analyzed for wear tracks at different temperatures to reveal the mechanism of low wear of the composite coating. Results showed that all of the coatings exhibit polycrystalline structures and the morphologies grow in an obvious columnar crystal. The CrN/Mo2N/MoSx composite coating presented a wear rate as low as 1.62 × 10−6 mm3/Nm and 6.63 × 10−7 mm3/Nm at 25 ℃ and 750 ℃, respectively. It is noted that MoS2 and Mo2N were preferential oxidation in comparison to CrN was conducive to lubrication at medium and high temperature. Additionally, a continuous protective glaze layer was generated within the wear track of the composite coating at 750 ℃ which was mainly consist of MoO3 generated in situ by the oxidation of Mo compounds with a higher affinity for oxygen. Meanwhile, the hard phase of CrN with outstanding oxidation resistance play a good bearing role during the friction process. This new type of composite coating provides a potential solution for the application of high-temperature wear-resistant coating under harsh working conditions for mechanical engineering.