TiC Thin Films Research Articles

Chemically Stable Group IV-V Transition Metal Carbide Thin Films in Hydrogen Radical Environments.

Hydrogen is a crucial element in the green energy transition. However, its tendency to react with and diffuse into surrounding materials poses a significant challenge. Therefore, developing coatings to protect system components in hydrogen environments (molecular, radicals (H*), and plasma) is essential. In this work, we report group IV-V transition metal carbide (TMC) thin films as potential candidates for protective coatings in H* environments at elevated temperatures. We expose TiC, ZrC, HfC, VC, NbC, TaC, and Co2C thin films, with native surface oxycarbides/oxides (TMO x C y /TMO x ), to H* at elevated temperatures. Based on X-ray photoelectron spectroscopy performed on the samples before and after H*-exposure, we identify three classes of TMCs. HfC, ZrC, TiC, TaC, NbC, and VC (class A) are found to have a stable carbidic-C (TM-C) content, with a further subdivision into partial (class A1: HfC, ZrC, and TiC) and strong (class A2: TaC, NbC, and VC) surface deoxidation. In contrast to class A, a strong carbide reduction is observed in Co2C (class B), along with a strong surface deoxidation. The H* interaction with TMC/TMO x C y /TMO x is hypothesized to entail three processes: (i) hydrogenation of surface C/O atoms, (ii) formation of CH x /OH x species, and (iii) subsurface C/O atom diffusion to the surface vacancies. The number of adsorbed H atoms required to form CH x /OH x species (i) and the corresponding thermodynamic energy barriers (ii) are estimated based on the change in the Gibbs free energy (ΔG) for the reduction reactions of TMCs and TMO x . Hydrogenation of surface carbidic-C atoms is proposed to limit the reduction of TMCs, whereas the deoxidation of TMC surfaces is governed by the thermodynamic energy barrier for forming H2O.

Comparative assessment and experimental analysis of atomic coordination and mechanical properties of sputter deposited Ti-rich TiN, TiC, and TiCN thin films

In the present work, Titanium nitride (TiN)150 nm, Titanium on Titanium nitride (TiN75 nm/Ti75 nm), Titanium on Titanium carbonitride (TiCN75 nm/Ti75 nm), and Titanium on Titanium carbide (TiC75 nm/Ti75 nm) films were deposited on Si (100), quartz, and glass substrates through dc-magnetron sputtering. Vacuum annelation was carried at 600ºC for 1 hr to form TiN (m-TiN), Ti-rich TiN (b-TiN), Ti-rich TiC (b-TiC) and Ti-rich TiCN (b-TiCN) films. b-TiCN showed less optical absorbance and band gap compared to b-TiN and b-TiC films and more detrimental types of defects, which might lead to the degradation of mechanical properties in b-TiCN film. The shifting of the Ti-N core orbital towards higher binding energy showed the higher bond strength of the b-TiN film. The ITA/ITO ratio increased from 0.8 to 2.37 for b-TiC to b-TiN films, signifying the deterioration in medium-range order. The defect parameter, ID/IG, increased from 0.63 to 0.71, indicating that b-TiCN has higher defects than b-TiC films. The valence band spectra revealed that b-TiN and b-TiC valence bands are present above the Fermi level but below in the case of b-TiCN films. X-ray absorption spectroscopy confirmed that the Ti L, N K, and C K-edge were observed at 462.38, 404.53, and 287.33 eV, respectively. The highest Young’s modulus and hardness were 97.43 and 18.47 GPa, respectively, measured by a Berkovich nanoindenter for b-TiN thin films.

Structural, nanomechanical and electrochemical properties of TiC and TiN films prepared by pulsed DC magnetron sputtering technique

The structural, nanomechanical and corrosion properties of TiC and TiN thin films prepared by pulsed dc sputtering under similar processing conditions were investigated. X-ray diffraction, scanning electron microscopy and atomic force microscopy techniques were used to investigate the phase formation, surface morphology, and surface roughness of the films, respectively. Nanoindentation technique revealed that the TiC films had superior indentation hardness and Young’s modulus of 18.61GPa, and 196.57 GPa, respectively than that of the TiN films. Electrochemical impedance spectroscopy measurements carried out in natural seawater and 3.5% NaCl solution indicated that TiC coating with low surface roughness has shown a superior passivation and better corrosion protection for the M−50 steel substrate than that of TiN coatings.

Influence of TiC thin film growth morphology deposited by RF magnetron sputtering on the mechanical and tribology properties of Ti6Al4V

The research study reported the influence of RF power and temperature on the growth morphology, mechanical property and tribology behaviour of TiC thin films deposited on Ti6Al4V by RF magnetron sputtering. The RF power used was between 150 and 250 W with an interval of 50 W and the temperature was between 70 and 90 °C at an interval of 10 °C. The surface morphology and topography were examined using Field Emission Scanning Electron Microscope FESEM and Veeco Di2100Atomic force microscopy. Hysitron Triboindenter was used to evaluate the nanohardness and other mechanical properties of the TiC thin film coating. The film adhesion and coefficient of friction were analysed on an Anton Paar Microscratch Tester. The TiC thin film morphology reveals denser and equiaxed films as the sputtering process parameters increase. The surface topography is characterized with high peaks of TiC thin film and the surface roughness reduces with increase in RF power and temperature. The nanohardness of the TiC thin films increases as the RF power and temperature decrease. The film adhesion shows good resistance to delamination and peeling of the TiC thin film under microscratch test for all the samples.

GIXRD, Raman and Surface analysis of TiC thin film coating produced by RF Magnetron Sputtering

In this research, TiC thin films were successfully deposited on Ti6Al4V substrate using RF magnetron sputtering under different RF power, temperature and sputtering time. The resulting properties of TiC thin film were characterized using Grazing incidence X-ray diffractometer (GIXRD), Raman spectroscopy, Field emission scanning electron microscope (FESEM) and optical profilometer for structural and surface morphology of the thin film. The results show that the properties of the TiC thin film were affected by the RF magnetron sputtering parameters. Preferential orientation (200) plane was noticed for all the coating. The Raman analysis revealed the presence of both D- mode which is as a result of structural disorder and G-mode which indicates presence of surface impurities and defects at RF power of 150 W. The thin films become homogeneous and densely packed at RF power of 200 W. The surface roughness was also investigated. The least surface roughness was found at RF Power of 200 W, time of 2.5 Hrs and temperature of 100 °C.

TiC/a-C Nano-Composite Films Fabricated by Using Closed-Field Unbalanced Magnetron Sputtering for Biomedical Applications

Hydrogenated amorphous carbon films (a-C:H or DLC) exhibit high hardness, low friction coefficient, and high wear resistance. Variations in the tribological properties were studied for amorphous carbon films fabricated by using closed-field unbalanced magnetron sputtering with TiC thin films as an adhesive layer. The a-C, a-C:Ti, and TiC/a-C nano-composite films were prepared using closed-field unbalanced magnetron sputtering with graphite and titanium as targets. Various structures of Ti-doped a-C and TiC interlayers under the amorphous carbon (a-C) film were examined to improve the tribological properties, and characteristic changes in the nano-composite structure were observed. The structure of the nano-composite film showed improved tribological properties, including high hardness, low friction coefficient, low surface roughness, and good adhesion of the a-C thin films. With a Ti-doped a-C film in a laminated structure, the tribological properties were improved to a high hardness value of >28.5 GPa, a high elastic modulus of >250 GPa, and a smooth surface with a roughness of <0.1 nm.

Grain boundary modification of TiC ultrananocrystalline thin films: Improvement in tribo-physical properties

This work reports on the influence of grain boundary modification on the tribological properties of nanocrystalline titanium carbide (nC-TiC) - amorphous carbon (a-C) nanocomposite films. TiC thin films were deposited by magnetron sputtering using TiC target in optimized hydrogen containing atmosphere. Nano/ultrananocrystalline TiC phase and short ranged ordered graphite phase were found to be dispersed in the a-C matrix in thin films. Chemical composition and also the chemical structure of the graphitized phase and a-C in the grain boundary were modified by controlling the substrate temperature. Raman spectroscopy showed that at room temperature, the films were dominated by a-C phase occupying the grain boundary. However, at moderate deposition temperature, graphitization of the film was observed and such modification was associated to the formation of short ranged crystalline graphite phase within a-C matrix. The friction coefficient was found to decreased with increase in the I(D)/I(G) ratio of Raman shift in the films. A sustainable ultralow value of friction coefficient was observed in the films with TiC nano/ultrananocrystalline phase surrounded by nanographitized domains. This could be associated to the layered lattice structure of short ranged graphite phase which readily shears and produces negligible frictional resistance. Sustainability of ultralow value of friction coefficient and high wear resistance are attributed to the formation of graphitized transfer film.

Comparison of the structure and topography of selected low friction thin films

Purpose: The purpose of this article is to characterize and compare the structure, mechanical and tribological properties of low friction DLC and TiC thin films deposited on the austenitic steel X6CrNiMoTi17-12-2 substrate. Design/methodology/approach: In the research, the samples of the DLC and TiC thin films with transition hard AlCrN interlayer deposited by magnetron sputtering and PACVD technology respectively were used. Observations of topography were made using a scanning electron microscope (SEM), and the atomic force microscope (AFM). The structure of samples was performed using a Raman microscope. The microhardness tests of thin films were made by Oliver &amp; Phare method. Findings: Studies confirmed that the combination of research SEM and AFM provide crucial information on the structure and topography of the samples. It was possible to obtain information about the topography parameters and allow for the assessment of morphology and quality of the tested coatings. Study of the structure using Raman spectroscopy revealed the band corresponding to the DLC and TiC thin films. Practical implications: The current application areas for low friction thin films are constantly growing, and the intensive development of techniques requires the use of new technologies what leads to the production of the specific surface layer and a thorough examination. Originality/value: Growing area of low friction coatings with specific properties requires the use of specialized tools aimed at assessing the topography and structures which are responsible for tribological properties.

(Invited) Wafer Level Fabrication Process of High Performance Micro-Supercapacitors

Nowadays, miniaturized power sources are key devices for providing autonomy to smart and connected sensors. To reach this goal, the current trend is to fabricate micro-storage unit such as microbatteries (MB) or microsupercapacitors (MSC) at the wafer level. According to the limited surface of such device, the metrics should be reported as normalized to the footprint area (mF, µWh and mW per cm2). With such metrics, the average energy density of most of MSC1,2 (Onions like carbon, graphene) is found to be close to 1 µWh/cm2which is not enough to get autonomous miniaturized and connected sensors. Within this study, two different approaches will be reported to significantly improve the performances of MSC. One attractive way to improve the areal energy density of MSC is to enhance the material mass loading while keeping low the footprint area. To meet this requirement3, on chip fabrication of 3D MSC is proposed. Wafer level fabrication process on high area enlargement factor 3D scaffold (AEF # 50) is achieved. Step conformal deposition of MnO2 thin film (electrophoretic deposition) on this 3D template is performed and the MSC are tested either in aqueous electrolyte (0.5M Na2SO4) or in EMI-TFSI aprotic ionic liquids (AILs). The areal energy density of the proposed micro-device is close to 10 µWh/cm2 while maintaining high areal power density of 10 mW/cm2. Carbon derived carbide (CDC) based MSC is the second followed way to propose on chip high performance device. The fine-tuned chlorination of TiC thin films deposited and patterned as interdigitated planar electrodes is performed in the framework of this study4. CDC based MSC were directly fabricated on silicon wafer. The corresponding areal energy density is around 1 µWh/cm2 for aqueous based device (1M H2SO4) and higher than 20 µWh/cm2 for MSC tested in organic electrolyte (2M EMI-BF4 in ACN). The power density is measured to be close to 100 mW/cm2. Finally, MSC based on vanadium nitride5 thin films grown either by sputtering technique (for planar MSC) or by atomic layer deposition technology (for 3D MSC) will be reported. The objective of these studies is to clearly find the suitable technology allowing to propose the fabrication of high areal energy density, small footprint area MSC and to move toward solid state configuration.

Thickness Effects of TiC Interlayer on Tribological Properties of Diamond-Like Carbon Prepared by Unbalanced Magnetron Sputtering Method.

We investigated the tribological properties of diamond-like carbon (DLC) films prepared with TiC interlayer of various thicknesses as the adhesive layer. DLC and TiC thin films were prepared using unbalanced magnetron (UBM) sputtering method using graphite and titanium as targets. TiC films as the interlayer were deposited under DLC films and various physical, tribological, and structural properties of the films fabricated with various TiC interlayer thicknesses were investigated. With various TiC interlayer thicknesses under DLC films, the tribological properties of films were improved with increasing thickness and the DLC/TiC layer fabricated by unbalanced magnetron sputtering method are exhibited maximum high hardness over 27 GPa and high elastic modulus over 242 GPa, and a smooth surface below 0.09 nm.

Hetero-epitaxial growth of TiC films on MgO(001) at 100 °C by DC reactive magnetron sputtering

Hetero-epitaxial TiC thin films were deposited at 100°C on MgO(001) by DC reactive magnetron sputtering in a mixture of Ar and CH4. The 62nm thick films were analyzed for elemental composition and chemical bonding by Auger electron spectroscopy, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. The crystallographic structure investigation by high resolution X-ray diffraction revealed that the films consist of two layers: an interface partially strained epilayer with high crystalline quality, and a relaxed layer, formed by columnar grains, maintaining the epitaxial relationship with the substrate.The films presented smooth surfaces (RMS roughness ~0.55nm), with circular equi-sized grains/crystallites, as observed by atomic force microscopy. The Hall measurements in Van der Pauw geometry revealed relatively high resistivity value ~620μΩcm, ascribed to electron scattering on interfaces, on grain boundaries and on different defects/dislocations.

마그네트론 스퍼터링법으로 증착시킨 TiC 박막의 물리적, 전기적 특성에서 RF 파워의 영향

TiC thin films were deposited on Si wafer by unbalanced magnetron sputtering (UBMS) system with two targets of graphite and titanium. During the TiC sputtering, the RF power was varied from 100 W to 175 W and the physical and electrical properties of TiC films were investigated. The hardness and rms surface roughness of TiC films were improved with increasing RF power and the maximum hardness about 24 GPa and the minimum rms surface roughness about 1.2 nm were obtained. The resistivity of TiC films was decreased with increasing RF power. Consequently, the physical and electrical properties of TiC film wewe improved with increasing RF power.

Three-dimensional thickness and property distribution of TiC films deposited by DC magnetron sputtering and HIPIMS

High power impulse magnetron sputtering (HIPIMS) is known for ionising a reasonable amount of the deposition particles emitted from a magnetron sputtering source. Besides improved density and mechanical properties of the deposited films a higher thickness uniformity in three-dimensional structures has also been reported as a benefit of this technology.In this work TiC thin films were deposited from a 50mm diameter TiC-target in Ar atmosphere using direct current magnetron sputtering (dcMS) and HIPIMS with a peak power density of 1kW/cm2. A special three-dimensional structure with three different drilled blind holes (10, 4 and 2mm diameter) was built and used as the substrate. Flat polished high speed steel samples were mounted as parts of the side wall and the bottom of each hole in such a way that the coating thickness and hardness could be detected afterwards at several locations. It turned out that in most cases HIPIMS did not show any improvement in the homogeneity of the film thickness. In fact mostly the dcMS deposited films even exhibited better thickness uniformity. However, the differences between dcMS and HIPIMS remained rather limited at an Ar pressure of 0.4Pa, whereas at 1Pa they have been much more significant. Applying a substrate bias voltage of −50V again nearly did not show any important impact. On the other hand the film properties in part changed distinctly. The hardness of the dcMS deposited TiC-films at the hole walls was up to 4 times lower than that of the HIPIMS deposited ones. Examination of the samples prepared by focused ion beam (FIB) and observed by scanning electron microscopy revealed a far more porous film morphology as an obvious reason for the severe drop of the hardness of the dcMS films at the side walls. The samples facing the magnetron exhibited very high hardness values (>2500HV) which were nearly independent of the deposition method.A detailed overview and discussion of the data will be provided, together with ionisation data obtained by optical emission spectroscopy.

Synthesis of Tic Thin Films by CVD from Toluene and Titanium Tetrachloride with Nickel as Catalyst

Titanium Carbide TiCx was deposited onto quartz substrates by the chemical vapour deposition (CVD) method. TiCx thin films were obtained from titanium tetrachloride (TiCl4) and toluene (C6H5CH3) as carbon source. Deposits were carried out in the range of substrate temperatures from 300 to 1100 C, with a source gas molar ratio (C6H5CH3/TiCl4 + C6H5CH3 ) of 0.8. There was two deposit processes; the first was to carry out without nickel as catalyst and the second with nickel as catalyst. Results showed that the effect of nickel as catalyst is very relevant to obtain TiCx. TiC0.87 thin films, 0.5 m thickness, were obtained for deposition temperatures above 900C using nickel as catalyst. In this case a cubic structure, with a lattice parameter of 4.327 A and a hardness of 2900 Vickers, was obtained at 11000C. whilst for substrate temperatures between 300 to 900°C with nickel as catalyst amorphous carbon samples were obtained. For the samples prepared without the presence of the nickel as catalyst only C amorphous thin films were obtained for all deposit temperatures.

Structure and corrosion resistance of Ti/TiC coatings fabricated by plasma immersion ion implantation and deposition on nickel–titanium

Titanium carbide coatings have a broad range of biomedical applications because of their high hardness, low friction, excellent corrosion resistance, and good biocompatibility. NiTi alloys are also widely used in surgical implants in orthodontics and orthopedics. In order to improve the surface properties, nanostructured titanium carbide coatings are deposited on NiTi by plasma immersion ion implantation and deposition after a titanium interlayer has been fabricated on the NiTi substrate. The structure and corrosion behavior which impact the biological properties are investigated systematically by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, and electrochemical impedance spectroscopy in simulated body fluids at 37°C. The TiC thin films with a C/Ti ratio of 1.087 have the (220) orientation. The EIS results demonstrate that the Ti/TiC multilayer provides significantly better corrosion resistance and stability compared to the uncoated NiTi substrate.

Hybrid Deposition of Titanium Carbide Thin Films

The aim of this paper is to describe hybrid pulsed laser magnetron technology (PLDMS) for deposition of both TiC and TiCN thin films. Films were fabricated in argon atmosphere (TiC) and argon/nitrogen mixtured atmosphere (TiCN). Titanium carbide based materials exhibit an unique combination of physical properties such as high hardness, low friction coefficient, high thermal conductivity, and high thermal stability. TiCN thin films are used for improvement of adhesion of carbon based thin films as an interlayer prior to carbon based deposition Film properties were studied by SEM, XRD, XPS and GDOES. The PLDMS method allows easily and smoothly change composition profile along layer thickness by changing of laser repetition rate and magnetron power. The PLDMS system is a suitable tool for fabrication of specially tailored layer at new deposition conditions.

Physicochemical and structural characteristics of TiC and VC thin films deposited by DC reactive magnetron sputtering

Vanadium carbide and titanium carbide films were deposited on Si substrates by direct current reactive magnetron sputtering, varying the substrate temperature during deposition and the reactive gas (CH4) pressure. The physicochemical and structural properties of the films were characterized for stoichiometric films (V/C = 1 and Ti/C = 1), which display good performance concerning wear, friction, and corrosion. The techniques used to characterize the films were Rutherford backscattering spectrometry in channeling geometry, 12C(α,α)12C nuclear resonant scattering, glancing angle X-ray diffraction, X-ray reflectometry, and X-ray photoelectron spectroscopy. The results revealed that the ideal conditions for deposition of these films are a CH4 partial pressure of 0.5 × 10−3 mbar and a substrate temperature of 400 °C. In such conditions, the deposition rates are 7 nm s−1 for TiC and 8.5 nm s−1 for VC at a target power density of 5.5 W cm−2. The density of the films, as determined here by X-ray reflectometry, are slightly higher than those for the bulk materials.

Microstructure and tribological properties of TiN, TiC and Ti(C, N) thin films prepared by closed-field unbalanced magnetron sputtering ion plating

TiN, TiC and Ti(C, N) films have been respectively prepared using closed-field unbalanced magnetron sputtering ion plating technology, with graphite target serving as the C supplier in an Ar–N 2 mixture gas. Bonding states and microstructure of the films are characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) in combination with transmission electron microscopy (TEM). The friction coefficients are measured by pin-on-disc test and the wear traces of deposited films are observed by optical microscope. Results show that the TiN film and Ti(C, N) film exhibit dense columnar structure while the TiC film exhibits a mixed microstructure of main nanocrystallite and little amorphous phases. The Ti(C, N) film has the highest microhardness value and the TiC film has the lowest. Because of small amount of pure carbon with sp 2 bonds existing in the film, the friction coefficients of Ti(C, N) and TiC multilayer films are lower than that of TiN film. In addition, the multilayer structure of films also contributes visually to decrease of friction coefficients. The TiC film has extremely low friction coefficient while the wear ratio is the highest in all of the films. The results also show that the Ti(C, N) film has excellent anti-abrasion property.

Study of TiC/a-C thin films growth by cathodic arc discharge varying the substrate temperature

TiC thin films were grown on 304 stainless steel substrates using the cathodic arc discharge (CAD) technique. Titanium (6N) was placed in the cathodic electrode and the substrate was placed on the anode, besides this electrode is a furnace. The substrate temperature was varied between 50 and 250 °C with increases of 50 °C. For producing the discharge, a critical damping RLC (C=0.54 mF, L=2.3 mH and R=0.46 mΩ) circuit was employed. To grow the TiC films, methane was used at a pressure of 3 mbar and a discharge voltage of 270 V. X-ray diffraction (XRD) showed the TiC-phase with broad peaks and low intensities, however, the films have a crystallographic texture coefficient for (111)-orientation. Using the Scherrer equation both the crystallite size and microstrain were determined. The crystallite size increased as a function of substrate temperature. Using x-ray photoelectron spectroscopy (XPS) technique, amorphous carbon and TiC were identified. Profiler depth was realized for identifying the distribution of both compounds in the film.

Surface brillouin scattering in opaque thin films

Simulations of surface Brillouin scattering (SBS) spectra of TiN, TiAlN, TiC and SiC thin hard films on silicon and diamond substrates have been carried out over a range of film thickness from 5nm to 1000nm. The simulations are based on the elastodynamic Green's function method that predicts the surface displacement amplitudes of acoustic phonons. These simulations provide information essential to understand and analyze experimental data emerging from SBS experiments currently in progress. There are striking differences in the simulated SBS spectra depending on the respective elastic properties of the film and the substrate. In fast on slow situations, the Rayleigh mode is accompanied by broadened resonances; in slow on fast situations, several orders of Sezawa modes are observed together with the Rayleigh mode and sharper resonances. In each case, use of a diamond substrate clearly provides optimal slow on fast conditions. Experimental studies are on process to demonstrate these effects. The velocity dispersion of the modes as a function of the product of surface wavevector and thickness (k//d) has also been simulated, allowing the elastic constants of the films to be determined.