Effect of Ti interlayer and bias on structure and properties of TiN films

The paper reports on properties and structure of the TiN films, which have been deposited on titanium interlayer covering a steel substrate. The Ti interlayer and the TiN film were prepared by d.c. magnetron sputtering in Ar and Ar + N₂ mixture, respectively. Three Ti interlayers with different thickness h _Ti = 0.01, 0.1 and 0.2 m were prepared under the same conditions and investigated. It was found that the macroscopic residual stress in the TiN films is compressive and increases with the increasing negative bias up to approximately –150V. Also the size of the TiN crystallites decreases with the increasing negative substrate bias, varying between 250 nm and 11 nm. The critical load, which characterises the film adhesion, increases with increasing h _Ti For h _Ti 0.1 m, the critical load almost does not depend on the bias voltage.     

Condensation Surface Temperature as a Means for Studying Film Formation Mechanisms

A rise in the condensation surface temperature during film growth is a result of energy dissipation on the condensation surface. An example of energy dissipation is the dissipation of chemical reaction heat, which releases during film deposition by reactive magnetron sputtering. The monitoring of the surface temperature during TiN film deposition by reactive (Ti–in–N₂) and nonreactive (TiN–in–Ar or TiN–in–N₂) sputtering methods has shown that this temperature is higher in the reactive case and decreases in the (TiN–in–Ar)–(TiN–in–N₂) sequence of nonreactive sputtering modifications. It has been found that the composition and crystal structure of TiN films do not depend on the growth method and are identical to those of bulk titanium nitride. Based on these results, a formation mechanism of films obtained by the above methods has been suggested. In the case of reactive sputtering, the film was supposed to grow on the condensation surface through a reaction between titanium and nitrogen atoms. In the cases of nonreactive sputtering, the film forms from TiN molecules.     

Characterization of Ti-Zr-N films deposited by cathodic vacuum arc with different substrate bias

Ti-Zr-N (multi-phase) films were prepared by cathodic vacuum arc technique with different substrate bias (0 to −500 V), using Ti and Zr plasma flows in residual N₂ atmosphere. It was found that the microstructure and mechanical properties of the composite films are strongly dependent on the deposition parameters. All the films studied in this paper are composed of ZrN, TiN, and TiZrN ternary phases. The grains change from equiaxial to columnar and exhibit preferred orientation as a function of substrate bias. With the increase of substrate bias the atomic ratio of Ti to Zr elements keeps almost constant, while the N to (Ti + Zr) ratio increases to about 1.1. The composite films present an enhanced nanohardness compared with the binary TiN and ZrN films deposited under the same condition. The film deposited with bias of −300 V possesses the maximum scratch critical load (L_c).     

Synthesis and characterization of superhard Ti-Si-N films obtained in an inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement

Using a novel inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement system, Ti-Si-N films were prepared on single-crystal silicon wafer substrates by sputtering Ti and Si (5 at.%:1 at.%) alloyed target in argon/nitrogen plasma. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), atomic force microscopy (AFM) and Nano Indenter XP tester were employed to characterize nanostructure and performances of the films. These films were essentially composed of TiN nanocrystallites embedded in an amorphous Si₃N₄ matrix with maximum hardness value of 44 GPa. Experimental results showed that the film hardness was mainly dependent on the TiN crystallite size and preferred orientation, which could be tailored by the adjustment of the N₂/Ar ratio. When the N₂/Ar ratio was 3, the film possessed the minimum TiN size of 10.5 nm and the maximum hardness of 44 GPa.     

Structural and tribological properties of nitrogen doped amorphous carbon thin films synthesized by CFUBM sputtering method for protective coatings

Nitrogen doped amorphous carbon (a-C:N) films are a material that may successfully compete with DLC coatings, which have high hardness, high wear resistance, and a low friction coefficient. The a-C:N films were prepared on silicon substrate by a closed-field unbalanced magnetron sputtering method with a graphite target and using the Ar/N₂ mixture gases. And, we investigated the effects of various DC bias voltages from 0 to −300 V on the structural and tribological properties of the a-C:N films. This study was focused on improving physical properties of the a-C:N film by controlling process parameters like negative substrate DC bias voltage. The maximum hardness of the a-C:N film was 23 GPa, the friction coefficient was 0.08, and the critical load was 25 N on a Si wafer. Consequently, the structural and tribological properties of the a-C:N film showed a clear dependence on the energy of ions bombardment and the density of the sputtering and the reaction gases during film growth.     

A magnetron sputtering technique to prepare a-C:H films: Effect of substrate bias

Amorphous hydrogenated carbon (a-C:H) films were deposited by magnetron sputtering with a mixture gas of Ar and CH₄. The a-C:H films deposited by this method have relatively low internal stress (<1 GPa) compared to some films deposited by conventional deposition process. The effects of substrate bias voltage on microstructure, surface morphology and mechanical properties of the films were investigated by various techniques. It has been found that the polymer-like structure is dominated at low bias voltage (−100 V), while the diamond-like structure with the highest hardness and internal stress is the main feature of the a-C:H films deposited under high bias voltage (−300 V). With increasing the bias voltage further, the feature of diamond-like structure decreases associating with the increase of graphitization. The frictional test shows that the friction coefficient and wear rate of the a-C:H films are depended strongly on structure and mechanical properties, which were ultimately influenced by the deposition method and bias voltage.     

氮化钛薄膜的光学性能分析

利用磁控溅射法，在不同的工艺条件下制备氮化钛薄膜。详细分析了不同工艺条件下薄膜的光谱选择特性以及相应的光学常数，通过俄歇电子能谱对薄膜的不同深度的元素成分进行了分析，由原子力显微镜测量并处理得到氮化钛薄膜的表面形貌图。结果表明，氮化钛薄膜的光学性能严格依赖于氮和钛原子数比，符合化学计量比的TiN薄膜具有良好的光谱选择性。基底加负偏压溅射可进一步改善薄膜的性能。     

The effect of bias voltage and working pressure on S/Mo ratio at MoS2-Ti composite films

S/Mo ratio has a crucial effect on the tribological properties of MoS₂-Ti composite films. The deposition parameters as such bias voltage and working pressure play a dominant role on the change of this ratio value. To determine the effect of working pressure and bias voltage on S/Mo ratio, MoS₂-Ti composite films were deposited on glass wafers by pulsed-dc magnetron sputtering (PMS). The deposition process was performed for nine different test conditions at various levels of target current, working pressure, and substrate voltage using the Taguchi L₉(3⁴) experimental method. It was observed that the chemical composition of MoS₂-Ti composite films was significantly affected by sputtering parameters. It was also observed that S/Mo ratio decreased as the bias voltage increased at a constant working pressure and S/Mo ratio increased with increasing working pressure at a constant bias voltage.     

Effects of experimental parameters on composition of boron carbon nitride thin films deposited by magnetron sputtering

We have synthesized boron carbon nitride thin films by radio frequency magnetron sputtering. The films structure and composition were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results indicate that the three elements of B, C, N are chemically bonded with each other and atomic-level hybrids have been formed in the films. The boron carbon nitride films prepared in the present experiment possess a disordered structure. The influence of PN₂/PN₂+Ar, total pressure and substrate bias voltage on the composition of boron carbon nitride films is investigated. The atomic fraction of C atoms increases and the fractions of B, N decrease with the decrease of PN₂/PN₂+Ar from 75% to 0%. There is an optimum total pressure. That is to say, the atomic fractions of B, N reach a maximum and the fraction of C atoms reaches a minimum at the total pressure of 1.3 Pa. The boron carbon nitride films exhibit lower C content and higher B, N contents at lower bias voltages. And the boron carbon nitride films show higher C content and lower B, N contents at higher bias voltages.     

Texturing effects in molybdenum and aluminum nitride films correlated to energetic bombardment during sputter deposition

Molybdenum films sputter-deposited at low pressure show a (110) to (211) texture turnover with increasing film thickness, which is accompanied by a transition from a fiber texture to a mosaic-like texture. The degree of (002) texturing of sputtered aluminum nitride (AlN) films strongly depends on nitrogen pressure in Ar/N₂ or in a pure N₂ atmosphere. For the understanding of these phenomena, the power density at the substrate during sputter deposition was measured by a calorimetric method and normalized to the flux of deposited atoms. For the deposition of Mo films and various other elemental films, the results of the calorimetric measurements are well described by a model. This model takes into account the contributions of plasma irradiation, the heat of condensation and the kinetic energy of sputtered atoms and reflected Ar neutrals. The latter two were calculated by TRIM.SP Monte Carlo simulations. An empirical rule is established showing that the total energy input during sputter deposition is proportional to the ratio of target atomic mass to sputtering yield. For the special case of a circular planar magnetron the radial dependence of the Mo and Ar fluxes and related momentum components at the substrate were calculated. It is concluded that mainly the lateral inhomogeneous radial momentum component of the Mo atoms is the cause of the in-plane texturing. For AlN films, maximum (002) texturing appears at about 250 eV per atom energy input. Received: 23 June 2000 / Accepted: 12 December 2000 / Published online: 3 April 2001     

Magnetism in nanometer-thick TiOx/Co/TiOx/TiN/Si multilayered structures

Most studies on Co-doped TiO₂ system were focused on thin films grown by MBE-based methods. In this work we report the ferromagnetism of nanometer-thick-layered TiO₂/Co/TiO₂/TiN film grown on Si substrate by conventional magnetron sputtering. For the growth of TiO₂ on silicon, a non-oxide thermally stable material, TiN, was introduced to prevent Ti penetration into the Si substrate. Structural, magnetic, and transport measurements respectively by Raman, SQUID and Hall effect show that our samples are n-type semiconductors and exchange bias effect due to exchange coupling between Co and interfacial CoO. For the rapid vacuum annealed specimen, we found an enhanced loss and a Perminvar-type constricted hysteresis loop, which attributed to pinning of domain walls due to an induced anisotropy by the pair ordering in the metallic alloy of Co-Ti-Si.     

Effects of deposition parameters on the structure and mechanical properties of high-entropy alloy nitride films

High-entropy alloy (AlCrNbSiTiV)N nitride films are prepared using direct current (dc) reactive magnetron sputtering, with an equiatomic AlCrNbSiTiV alloy target. Experiments using the grey-Taguchi method are conducted to determine the effect of deposition parameters (dc power, substrate temperature, N₂/(N₂+Ar) flow rate and substrate bias) on the microstructure, mechanical and tribological properties. Orthogonal array (L₉ 3⁴), signal-to-noise ratio and analysis of variance are used to analyze the effect of the deposition parameters. The coated films are examined using scanning electron microscopy, an atomic force microscope, transmission electron microscopy (TEM), a tribometer and a nanoindenter. The TEM patterns confirm that the (AlCrNbSiTiV)N nitride films have a simple face-center-cubic structure. The experimental results show that a (AlCrNbSiTiV)N film coating significantly improves the mechanical properties. In the confirmation runs, using grey relational analysis, the improvement in friction coefficient is 32.5%, in corrosion current is 28.6%, in hardness H is 29.4%, in elastic modulus E is −18.3%, in H/E is 57.1 and in H³/E² is 225.0%. The samples with (AlCrNbSiTiV)N film coating are classified as HF1 and exhibit good adhesive strength.     

In situ identification of organic components of ink used in books from the 1900s by atmospheric pressure matrix assisted laser desorption ionization mass spectrometry

Transport of N, O, and Ti during dc magnetron sputtering deposition of nanoscopic TiN/Ti and TiN structures on plasma nitrided M2 tool steel, as well as transport of metallic species composing the plasma nitrided steel substrates were investigated. N and O depth distributions were determined with subnanometric resolution using narrow resonant nuclear reaction profiling, whereas Ti was profiled, also with subnanometric depth resolution, by medium energy ion scattering. The surface elementary compositions of the TiN/Ti/nitrided steel and TiN/nitrided steel structures were determined by low energy ion scattering. The chemical compounds formed during deposition were accessed by X-ray photoelectron spectroscopy, indicating the presence of TiN, TiO₂, Ti oxynitrides, as well as other metallic nitrides and oxynitrides, but no metallic Ti was observed. Owing to the observed intensive atom mobility, the compositions of the deposited films on plasma nitrided steel structures varied continuously on a nanoscopic scale, from the core of the steel substrate to the bulk of the stoichiometric TiN films. The Ti interlayer assists interdiffusion of all species, in contrast to the TiN film layer, which is known to be a diffusion barrier. The improved adhesion of TiN hard coatings to plasma nitrided steel under working conditions is discussed in terms of the gradual compositional change around the interfaces and the atomic mobility during their formation.     

Pulsed magnetron sputtering and ion-induced annealing of carbon films

Thin carbon films are deposited on a silicon substrate at room temperatures via the biased pulsed magnetron sputtering of graphite in the physical (Ar, Kr, Xe) and reactive (Ar: CH4) modes at a different sputtering power density varying from 40 to 550 W/cm². To ensure ion-assistance, negative bias of the substrate is set during film deposition by means of both DC and pulsed power sources. Some deposition parameters lead to a high hardness of the films (12.5 GPa), optical transparency, a surface resistance of RS > 10⁹ Ω/h, and developed nanomorphology of the sample surface which bears visible inclusions with a lateral size of 35 nm. Some of the films are annealed after deposition with a C⁺-ion beam with an energy of 20 keV. A correlation between the parameters of magnetron deposition and ion-beam modification and the examined characteristics of the films is found. Different R _S values in a wide range can be achieved by means of simple adjustment of the parameters and modes during magnetron sputtering and ion-beam modification.     

The characterization of fluorocarbon films on NiTi alloy by magnetron sputtering

Fluorocarbon films were deposited on nickel-titanium (NiTi) alloy substrate by radio-frequency (RF, 13.56 MHz) magnetron sputtering using a polytetrafluoroethylene (PTFE) target. The deposition parameters of fluorocarbon films including the RF power, the working gas pressure and Ar flow rate were systematically studied. The structure of the deposited films was studied by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The surface morphology of the deposited films was measured by atomic force microscopy (AFM). The mechanical properties of the deposited films were characterized by a nanoindenter. C-Fx and C-C units were found in the deposited fluorocarbon films, which corresponded to the results of XPS. The surface roughness of the fluorocarbon film was 7.418 nm (Ra).     

Diffusion and chemical composition of TiNxOy thin films studied by Rutherford Backscattering Spectroscopy

Thickness and chemical composition of the TiN_xO_y thin films deposited by reactive magnetron sputtering from Ti target at controllable oxygen flow rate were determined by Rutherford Backscattering Spectroscopy (RBS) using 2 MeV He⁺ ions. The films were deposited on carbon foils and amorphous silica (a-SiO₂) substrates at 25 °C and 250 °C. The estimated film thickness is of 75-100 nm. The O/Ti atomic ratio in the films increases up to 1.5 with increasing oxygen flow rate, while that of N/Ti decreases from about 1.1 for TiN to 0.4 at the highest oxygen flow rate. Substantial out-diffusion of carbon from the substrate is observed which is independent of the substrate temperature. Films grown onto a-SiO₂ substrates can be treated as homogeneous single layers without interdiffusion. It is more difficult to determine the nitrogen and oxygen content due to superposition of RBS signals arising from film and substrate. RBS analysis of the depth profile indicates that for the investigated films the carbon diffusion and oxidation not only at the topmost surface layers but over the bulk of the films were found. Comparison with XPS results indicates substantial oxygen adsorption at the surface of TiN_x thin films obtained at zero oxygen flow rate.     

Ion beam sputter deposition of TiO<Subscript>2</Subscript> films using oxygen ions

TiO₂ thin films were grown by ion beam sputter deposition (IBSD) using oxygen ions, with the ion energy and geometrical parameters (ion incidence angle, polar emission angle, and scattering angle) being varied systematically. Metallic Ti and ceramic TiO₂ served as target materials. The thin films were characterized concerning thickness, growth rate, surface topography, structural properties, mass density, and optical properties. It was found that the scattering geometry has the main impact on the film properties. Target material, ion energy, and ion incidence angle have only a marginal influence. Former studies on reactive IBSD of TiO₂ using Ar and Xe ions reported equivalent patterns. Nevertheless, the respective ion species distinctively affects the film properties. For instance, mass density and the refractive index of the TiO₂ thin films are remarkably lower for sputtering with oxygen ions than for sputtering with Ar or Xe ions. The variations in the thin film properties are tentatively attributed to the angular and the energy distribution of the film-forming particles, especially, to those of the backscattered primary particles.     

基片偏压对MCECR溅射硬碳膜特性的影响

采用封闭式电子回旋共振(MCECR)氩等离子体溅射碳靶的方法在硅片上沉积了高质量的硬碳膜, 膜层厚度约40 nm. 使用X射线光电子能谱仪(XPS)和高分辨率透射电子显微镜(HRTEM)分析了碳膜结构,并用POD摩擦磨损仪测试了碳膜的摩擦磨损特性,用纳米压入仪测试了碳膜的纳米硬度.详细研究了基片偏压对碳膜的结构、摩擦磨损特性以及纳米硬度的影响,得到了最佳基片偏压.     

Optimization of plasma parameters for high rate deposition of titanium nitride films as protective coating on bell-metal by reactive sputtering in cylindrical magnetron device

Nano-structured titanium nitride (TiN) thin film coating is deposited by reactive sputtering in cylindrical magnetron device in argon and nitrogen gas mixtures at low temperature. This method of deposition using DC cylindrical magnetron configuration provides high uniform yield of film coating over large substrate area of different shapes desirous for various technological applications. The influence of nitrogen gas on the properties of TiN thin film as suitable surface protective coating on bell-metal has been studied. Structural morphological study of the deposited thin film carried out by employing X-ray diffraction exhibits a strong (2 0 0) lattice texture corresponding to TiN in single phase. The surface morphology of the film coating is studied using scanning electron microscope and atomic force microscope techniques. The optimized condition for the deposition of good quality TiN film coating is found to be at Ar:N₂ gas partial pressure ratio of 1:1. This coating of TiN serves a dual purpose of providing an anti-corrosive and hard protective layer over the bell-metal surface which is used for various commercial applications. The TiN film's radiant golden colour at proper deposition condition makes it a very suitable candidate for decorative applications.     

脉冲直流偏压增强的高质量立方氮化硼薄膜的合成

采用磁增强活性反应离子镀系统成功地合成了立方氮化硼薄膜.通过给基片施加脉冲直流偏压以代替传统的射频偏压,增强了立方氮化硼的成膜稳定性,研究了基片的直流脉冲偏压、等离子体放电电流、通入气体流量比(Ar/N₂)和基片温度沉积参数对立方氮化硼薄膜形成的影响规律.结果表明:随着基片负偏压和放电电流的增大,薄膜中立方氮化硼的纯度提高,当基片负偏压为155V,放电电流为15A时,可获得几乎单相的立方氮化硼薄膜.基片温度为500℃和Ar/N₂流量比为10时,最有利于立方氮化硼 关键词： 立方氮化硼 活性反应离子镀 脉冲偏压