Physical Vapor Deposition Sputtering Research Articles

Structural and Mechanical Characterization of Duplex Multilayer Coatings Deposited onto H13 Tool Steel

Quenched and tempered H13 tool steel was plasma nitrided and Physical Vapour Deposition (PVD) coated in a hybrid reactor aiming to obtain a TiN/TiC multilayer coating deposited on a plasma nitrided substrate, with a more gentle transition of elastic-plastic properties between the outermost layer of the coating and the substrate. Duplex treatment (plasma nitriding and PVD coating) was carried out in a hybrid reactor. Plasma nitriding preceded the DC triode magnetron sputtering PVD process, conducted inside the same chamber, using CH 4 and N 2 as reactive gases. Multilayer TiN/TiC coatings deposited on a nitrided H13 substrate were obtained. The multilayer coating was composed by a first Ti interlayer to grant adhesion, followed by a second 18.4 at% C TiC layer with a cF8 NaCl type unit cell, then a 41.9 at% N TiN layer and finally an outermost 32.3 at% C TiC layer with the same cF8 NaCl type unit cell. The multilayer coating showed a gentle transition of elastic-plastic properties assessed by the H/E * and the H 3 /E *2 ratios and the elastic recovery as a function of the distance from the surface of the specimen. The adhesion of the multilayered coating to the substrate was greater in the case of the duplex coated specimen as compared to the non duplex treated H13 steel.

Effective Gap Filling via Magnetic Field Simulation Assisted on Longthrow Sputtering PVD of Side Magnet Designs and Arrangements for 3DIC Application

This study used Finite Volume Method to simulate the magnetic profile of PVD (physical vapor deposition) chamber. For this longthrow PVD, the adaptor of the gap filling chamber has 120 mm height and 44 sets of side magnets around the adaptor. The polarity of the side magnets is the same as the top magnets of the chamber. These side magnets can very effectively increase electron mobility and collision frequency with sputtered atoms. The plasma simulation result shows that ionization rate on sputtered atoms can be up to 12% from such a PVD system along with such a magnet arrangement. Therefore, it shows a significant improvement on bottom side-wall coverage of via hole up to 45%. The deposition rate increases by 40%. In addition, the adjustment of RF bias and resputtering power can result in further improvement on 3/4 depth of side-wall coverage by 30% and corner step coverage by 70%. This study uses a simple method to apply 3DIC gap filling capability for an increase of aspect ratio (AR).

Indium tin oxide coatings properties as a function of the deposition atmosphere

Indium tin oxide coatings were deposited by magnetron sputtering physical vapour deposition under different atmospheres. Microstructural, electrical, and optical properties were measured, finding a correlation among properties and process parameters. Texture analyses carried out by X-ray diffraction showed that films microstructure depended by the oxygen content in the deposition vessel: high values of the oxygen content (e.g., 5%) caused the film to grow along the <111> orientation; under pure Ar, the grains grew along the <100> orientation. Intermediate values of the oxygen content caused the growth of two families of grains, respectively oriented along the <111> and the <100> directions.

Side Magnet Designs and Magnetic Field Effects on Effective Gap Filling of Longthrow Sputtering PVD for 3DIC Application

This study used Finite Volume Method to simulate the magnetic profile of PVD (physical vapor deposition) chamber. It can be applied to different kinds of magnet arrangements to the longthrow sputtering PVD. For this long throw PVD, the best optimized process conditions and results from simulations included effects from chamber adaptor height, side magnet space, and magnet arangements. The side magnets consist of a total of 44 sets for one supporter around the chamber adaptor. Each set has three magnets. Each magnet has the magnetic field strength of 5,500 Gauss. The adaptor of gap filling chamber has a height of 120 mm and 44 sets of magnets around the adaptor. The polarity of side magnets is the same as the top magnets of the chamber. These magnets can very effectively increase of electron mobility and collision frequency with sputtered atoms. The plasma simulation result shows that the ionization rate on supttered atoms can be up to 26% from such a longthrow PVD system along with such magnets arrangement. Therefore, it shows a significant improvement on bottom side-wall step coverage in via hole up to 45%. The deposition rate increases by 40%. In addition, by adjusting RF bias and resputtering power, further improvement with 3/4 depth of side-wall step coverage by 30% and corner step coverage by 70% can be obtained. This study uses a simple method to apply to 3DIC gap filling capability for an increase of aspect ratio (AR). The improvement from this longthrow sputtering PVD with side magnets design around the adaptor not only results in low cost target design but also provides a very effective gap filling capability with higher deposition rate for 3DIC application.

DC-MSIP/HPPMS (Cr,Al,V)N and (Cr,Al,W)N thin films for high-temperature friction reduction

The application of high-strength steel and aluminum alloys entails increasing demands on the surfaces of tools used for forming processes. A promising approach towards the reduction of friction forces and thus towards the wear of tools is the application of self-lubricating coatings. Due to the high number of crystallographic shear planes and a partially low melting temperature, the so-called Magnéli-phases offer excellent possibilities for the reduction of friction in tools at application temperatures between 600 °C and 800 °C. In order to achieve the aforementioned gliding planes vanadium (V) and tungsten (W) containing (Cr,Al)N thin films deposited via a combination of Magnetron Sputter Ion Plating (MSIP) and High Power Pulse Magnetron Sputtering (HPPMS) Physical Vapor Deposition (PVD) were activated in a high-temperature environment. In this context, the (Cr,Al)N matrix provides for wear protection while vanadium and tungsten are developing friction-reducing oxides under temperature influence. Hence, a diffusion of these metals to the surface during application is necessary for a continuous generation of dry or liquid lubricants. Within this paper a scanning electron microscope (SEM) was used for the analysis of the cross-section fractures of the coatings in order to allow statements about the coatings' morphology and thickness; further, annealing tests in an atmosphere furnace at 600 °C, 800 °C and 1000 °C were carried out. X-ray diffractometry (XRD) served for documentation of phase transformations. With an electron probe micro analysis (EPMA) the diffusion of elements was observed. To investigate the friction reduction high-temperature pin-on-disk (PoD) tribometer measurements (room temperature (RT), 600 °C and 800 °C) using a 100Cr6 counterpart were, moreover, carried out in atmosphere. Within these investigations we could show a reduction in the friction coefficient from 0.6 at room temperature to 0.05 at 800 °C for the (Cr,Al,V)N coating. Furthermore, a diffusion of V to the surface of the coating was demonstrated. However, a positive effect by using (Cr,Al,W)N cannot be verified.

Nanomechanical and Electrochemical Properties of Diamond-Like Carbon (DLC) Films Deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) Technique

Diamond-like carbon (DLC) films was deposited successfully on stainless steel substrates with Si/SiC intermediate layers by combining plasma enhanced unbalanced magnetron sputtering physical vapor deposition (PEUMS-PVD) and microwave electron cyclotron resonance plasma enhanced chemical vapor deposition (MW-ECR PECVD) techniques. The effect of silicon dopant on the structure, morphology, nanomechanical properties and electrochemical behavior of DLC films were investigated by Raman spectroscopy, nano-indentation, atomic force microscopy (AFM) and potentiodynamic method and electrochemical impedance spectroscopy (EIS). It showed that the incorporated silicon atoms substituted sp2-bonded carbon atoms in the ring structures, promoting the formation of sp3-bonds. The structural transition from C-C to C-Si bonds resulted in the relaxation of the residual stress, leading to the decrease in films hardness. The DLC films with Si/SiC intermediate layers led to significant improvement in the corrosion resistance of the stainless steel substrate due to effective isolation and good chemical inertness of the DLC films.

Time resolved optical emission spectroscopy of an HPPMS coating process

This paper deals with the time resolved optical emission spectroscopy of a high power pulse magnetron sputtering (HPPMS) physical vapour deposition coating process. With an industrial coating unit CC800/9 HPPMS (CemeCon AG, Würselen) a (Cr,Al,Si)N coating was deposited. During the coating process, an absolute calibrated Echelle spectrometer (ESA-3000) measured the intensities of the spectral lines of chromium (Cr), aluminium (Al) and molecular bands of nitrogen (N2). Time resolved measurements enable us to calculate different parameters such as the average velocity of sputtered Al and Cr atoms or the internal plasma parameters electron density ne and electron temperature kTe with a time resolution of 20 µs. With these parameters, we determine the ionization rates of Al, Cr, Ar and Kr atoms and the deposition densities of Al and Cr atoms. Thus simulated deposition densities of 1.75 × 1020 m−2 s−1 for chromium and 1.7 × 1022 m−2 s−1 for aluminium are reached.

Correlation Between Sputtering Conditions and Growth Properties of (TiAl)N/AlN Multilayer Coatings

Multilayered coatings show better thermo/mechanical properties than monolayered coatings in cutting tool applications. In this study, TiAlN/AlN multilayer coatings were produced using diffirent magnetron sputtering physical vapor deposition (PVD) process parameters. Magnetron discharge power, bias voltages, and N2 flow rate will change growth morphology and surface quality of the coatings. The microstructure and growth morphologies correlated to sputtering conditions in a range of TiAlN/AlN multilayer coatings with nanoscale bilayer period thickness investigated carefully in order to identify the excellent properties of the coatings. Surface and fracture surfaces were characterized by scanning electron microscopy (SEM).

Effect of bias voltage on the electrochemical properties of TiN coating for polymer electrolyte membrane fuel cell

The electrochemical properties of TiN film coated on AISI 316 stainless steel (SS) by the magnetron sputtering physical vapor deposition (PVD) were studied for application as a bipolar plate. The crystal structure and surface morphology of the coatings were examined by x-ray diffractometry (XRD) and atomic force microscopy (AFM), respectively. The corrosion behaviors of the TiN films were investigated by electrochemical methods, including potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) under + 600 mV SCE application. The electrochemical behavior of the TiN coatings was enhanced with increasing bias voltage due to lower corrosion current density and higher R ct values during an immersion time of 168 h. This result was attributed to the formation of crystalline-refined TiN(200) at high bias voltage, which increased the coating compactness and the protective efficiency, and decreased passive current density.

Characterization of Anode-Supported Solid Oxide Fuel Cells With PSCF Cathode

A systematic study was initiated of anode-supported single cells with Pr0.58Sr0.4Co0.2Fe0.8O3−δ (PSCF) cathode. These solid oxide fuel cells (SOFCs) were characterized by electrochemical and diffusion and permeation measurements. In particular, the influence of various sintering temperatures of the cathode and various types of Ce0.8Gd0.2O2−δ (CGO) interlayer was investigated in more detail. Results from electrochemical measurements performed between 650°C and 800°C showed that the performance of anode-supported SOFCs with screen-printed porous CGO interlayer and a PSCF cathode was excellent. Even at 650°C, the area-specific resistance was lower than 0.5Ωcm2. The microstructure of the cathode and the performance of this type of SOFC were not obviously affected by variations in the sintering temperature of the cathode. Higher electrochemical performance, in particular, in the temperature range 650–750°C, was achieved by applying a thin and dense CGO interlayer using reactive sputtering or electron beam physical vapor deposition.

Electrochemical Behavior of CrN Coated on 316L Stainless Steel in Simulated Cathodic Environment of Proton Exchange Membrane Fuel Cell

Four types of CrN coating were deposited on type 316L stainless steel by magnetron sputtering physical vapor deposition (PVD) for use in bipolar plates. Four samples deposited at various bias voltages were evaluated under potentiodynamic, potentiostatic, and electrochemical impedance spectroscopy (EIS) conditions. EIS data were monitored for 96 h in an aerated corrosive environment at 70 °C to determine coating performance at +600 mV application. The electrochemical behavior of the coatings was enhanced with decreasing bias voltage. The CrN films on the 316L stainless steel substrate exhibited high protective efficiency, that is, increasing corrosion resistance with decreasing bias voltage. X-ray diffraction (XRD) analysis confirmed the formation of crystalline-refined CrN(200) at a low bias voltage.

Studies of diamond-like carbon (DLC) films deposited on stainless steel substrate with Si/SiC intermediate layers

In this work, diamond-like carbon (DLC) films were deposited on stainless steel substrates with Si/SiC intermediate layers by combining plasma enhanced sputtering physical vapour deposition (PEUMS-PVD) and microwave electron cyclotron resonance plasma enhanced chemical vapour deposition (MW-ECRPECVD) techniques. The influence of substrate negative self-bias voltage and Si target power on the structure and nano-mechanical behaviour of the DLC films were investigated by Raman spectroscopy, nano-indentation, and the film structural morphology by atomic force microscopy (AFM). With the increase of deposition bias voltage, the G band shifted to higher wave-number and the integrated intensity ratio ID/IG increased. We considered these as evidences for the development of graphitization in the films. As the substrate negative self-bias voltage increased, particle bombardment function was enhanced and the sp3-bond carbon density reducing, resulted in the peak values of hardness (H) and elastic modulus (E). Silicon addition promoted the formation of sp3− bonding and reduced the hardness. The incorporated Si atoms substituted sp2− bond carbon atoms in ring structures, which promoted the formation of sp3-bond. The structural transition from C—C to C–Si bonds resulted in relaxation of the residual stress which led to the decrease of internal stress and hardness. The results of AFM indicated that the films was dense and homogeneous, the roughness of the films was decreased due to the increase of substrate negative self-bias voltage and the Si target power.

MoSx lubricant coatings produced by PVD technologies

Among the different options for solid lubrication, MoS2 is probably the most attractive due to its extremely low friction levels. Recent developments in magnetron sputtering physical vapour deposition (PVD) technology have allowed the development of MoS2 composite thin films with more compact structures, low friction behaviour and enhanced wear resistance, reducing degradation by humidity. The present work provides an overview of recent developments in dry lubrication with MoS2 films deposited by modern sputtering PVD and how these MoS2 films alloyed with Ti or WC can outperform conventional unalloyed films not only under vacuum but also under atmospheric high humidity conditions. MoSx–WC composite films outperform MoSx–Ti films, showing endurance at 0·75 GPa as high as 1·2 million wear cycles, also significantly higher than the values obtained from unalloyed, conventional MoS2 thin solid films. The films also exhibit a steady state friction coefficient from 0·02 to 0·04. In addition, these films also show resistance to humid environment when tested under atmospheric conditions.

Diamond-like carbon (DLC) films deposited on copper substrate through preparation of intermediate layers

Diamond-like carbon (DLC) films were prepared on copper substrate through preparation of intermediate layers by combined plasma enhanced sputtering physical vapor deposition and microwave electron cyclotron resonance plasma enhanced chemical vapor deposition techniques. Raman spectroscopy indicated that the films had amorphous structure and typical characteristic of DLC film. With the increase of deposition bias voltage, D and G band both shifted to high wave-number and ID/IG increased gradually. The morphology was characterized by atomic force microscopy (AFM) and the results indicated that the films were dense and homogeneous , and the roughness of the films decreased with the increase of the deposition bias voltage. Hardness and modulus of DLC were measured by the nanoindentation.

The effect of annealing duration at deposition temperature on the strength properties gradation of PVD films and on the wear behaviour of coated cemented carbide inserts

Strength properties alterations may occur in the already deposited film material during the physical vapour deposition (PVD), induced by annealing, at the process temperature. Similar annealing mechanisms occur in PVD films during heat treatments, at a temperature corresponding to the temperature of the deposition. In the described investigations, cemented carbide inserts were coated through high ionisation sputtering PVD processes with a (Ti46Al54)N film, keeping all process parameters constant except the deposition time, which was set according to the desired film thicknesses. The coated specimens were isothermally annealed at deposition temperature for various time periods. The occurred coating superficial stress–strain laws were determined versus the film thickness through nanoindentations and a FEM-based evaluation method of the corresponding results. The detected film strength properties were correlated to the performance of the corresponding coated cutting inserts. In this way, annealing durations dependent on the coating thickness were predicted, enhancing the tool wear resistance in milling. Finally, the obtained results were theoretically explained by means of a FEM-simulation of the cutting process.

Field Emission Characteristics of Bn Films Treated withH2 and O2 Plasma

BN films were synthesized on the (100)-oriented surfaceof n-Si (0.008–0.02 Ωm) by rf magnetron sputtering physical vapordeposition (PVD). A BN film was first treated with H2 plasma for60 min and then the H2 treated sample was treated with O2plasma for 15 min. The films were characterizes by using Fouriertransform infrared spectra (FTIR) and atomic force microscopy (AFM).The field emission characteristics of BN films were measured in anultrahigh vacuum system. A turn-on electric field of 8 V/μm and acurrent of 400 μA/cm2 were obtained for the BN film treated withH2 plasma. The results show that the surface plasma treatmentmakes no apparent influence on the surface morphology of the BN films.The transformations of the sample emission characteristics have to dowith the surface negative electron affinity (NEA) of the filmspossibly. The turn-on electric field of the BN film treated withH2 plasma is lower than that without treatment, which possiblyattributes to the surface NEA effect. The surface NEA of the H2treated BN film is lost after O2 plasma treatment.

Deposition of c-BN on silicon substrates coated with diamond thin films

By controlling the pretreatment processes and deposition parameters on silicon substrates, diamond thin films with different surface roughness and sp2/sp3 ratio were used as an interlayer for subsequent c-BN (cubic boron nitride) thin film deposition studies. The diamond interlayers were prepared by microwave plasma chemical vapor deposition (CVD), while the c-BN top layers were prepared by unbalanced magnetron sputtering physical vapor deposition. The substrate curvature changes before and after the c-BN deposition were measured to better understand the relationship between film stress and adhesion to the diamond. In the range of our experimental parameters, results showed that a rougher surface and higher ratio of sp2/sp3 in the diamond layer improves the adhesive strength of the c-BN layer. An optimized layer structure of Si/diamond/BN is established. Grading of the diamond layer is expected to be helpful for adhesion enhancement of c-BN thin films on diamond interlayers.

Fabrication and characterization of nanometer CaP(aggregate)/Al 2O 3 composite coating on titanium

Nanometer CaP(aggregate)/Al 2O 3 composite coating on titanium for implant application has been successfully fabricated using a hybrid technique of anodization and hydrothermal treatment. Techniques, such as X-ray diffraction (XRD), scanning electron microscopy and energy disperse X-ray analysis (SEM+EDX), and transmission electron microscopy (TEM), have been used to investigate the composition, microstructure and morphology of the fabricated CaP(aggregate)/Al 2O 3 composite coating. SEM and EDX studies show that pure Al thin film is uniformly deposited on titanium substrate using magnetron sputtering physical vapor deposition (PVD) technique, and porous anodic aluminium oxide (AAO) film containing Ca and P are formed after anodization. XRD result indicates that the fabricated composite coating contains Al 2O 3 and various calcium phosphate phases. SEM and TEM results show that the crystals of CaP aggregates are in nanometers. It is also found that the fabricated nanometer CaP(aggregate)/Al 2O 3 composite coating is characterized by a porous cylindrical microstructure after hydrothermal treatment, which could lead to better biological and mechanical properties. In addition, anodization voltage is shown to have significant effects on the extent of anodization of the AAO film, and the optimal voltage is in the range 40–50 V.

Screening Wear Tester Versus Hip Joint Simulator: Results of UHMWPE Sliding Against Different CoCrMo Counterfaces

The wear of ultra high molecular weight polyethylene (UHMWPE) articulating against different CoCrMo counterfaces was tested with unidirectional sliding motion using a reciprocating pin on flat machine (RPOF) in accordance with ASTM 732. The results were compared with wear data obtained from the same material combinations using a hip joint simulator (HJS) featuring a multidirectional sliding motion (biaxial rocking motion). There were three CoCrMo surfaces: a forged CoCrMo alloy (ISO 5832-12), which was subjected to an industrial mass finishing treatment, the same alloy with a hand polished surface finish and a CoCrMo coating applied to the forged CoCrMo alloy by magnetron sputtering physical vapour deposition. The results show that the linear reciprocating motion led to a deterioration of the PVD coating causing significantly higher UHMWPE wear compared to the mass finished and hand polished forged CoCrMo alloy. However, the same CoCrMo coating caused significantly less UHMWPE wear than the forged CoCrMo alloys in the HJS. These results highlight the importance of selecting the correct choice of sliding motion, suggesting that this type of coating may be promising for applications in which multidirectional sliding predominates, for example, as a coating on femoral heads in artificial hip joints.

Thermal stability of magnetron and ion beam sputtered top and bottom spin-valve films

The thermal stability of top and bottom IrMn exchange-biased spin-valve films prepared by ion beam deposition (IBD) and magnetron sputtering physical vapor deposition (PVD) is compared. These films exhibit identical temperature dependence for the exchange bias field Hex, with a blocking temperature of TB=250 °C, that is independent of preparation technique. Isothermal annealing at temperatures below TB led to a ln(t) dependent degradation in Hex, suggesting a thermal activation process. The high crystallographic quality of the IBD films leads to a superior stability compared to PVD films. Top spin-valve films are also found to be more stable than bottom spin-valve films.