Titanium Carbide Films Research Articles

High Temperature Stable Titanium Carbide Ohmic and Schottky Contacts to SiC

ABSTRACTEpitaxial titanium carbide is investigated as a low resistivity, high temperature stable Ohmic and Schottky contact to 4H and 6H SiC. The titanium carbide films were deposited at 500°C using co-evaporation of titanium (e-beam) and C60(Knudsen cell) in a UHV system. Schottky diodes and TLM structures were fabricated on low and high doped SiC material respectively. The samples were annealed at 700 °C in a vacuum furnace, and electrical measurements were performed up to 300 °C.

Nanocrystalline titanium carbide thin films deposited by reactive magnetron sputtering

We investigated the structure and composition of titanium carbide thin films deposited by the reactive magnetron sputter ion plating process as a function of deposition parameters. The films were sputtered onto unheated glass substrates by means of an unbalanced planar d.c. magnetron equipped with a titanium target using a mixture of argon and methane. The deposition parameters ranged from 0.05 Pa to 2 Pa for total working gas pressurep T, from 10% to 60% (volume) for relative methane concentration in the working gas mixture, from 45 mm to 85 mm for the substrate-to-target distanced s-t and from −50V to −800V for the substrate biasU S. It was found that the crystallinity of the thin films strongly decreases with increasingp T,d s-t andU S. The experiments described show the conditions necessary to obtain sputter-deposited nanocrystalline titanium carbide films.

Low temperature deposition of epitaxial titanium carbide on MgO(001) by co-evaporation of C60 and Ti

Films of epitaxial titanium carbide were grown on MgO(001) at 400 and 500 °C using a novel method based on the co-evaporation of Ti and C60. Mirrorlike, adhesive films of TiC1-x (0.2<x<0.4) were deposited at growth rates of approximately 0.1 μm/h. X-ray diffraction showed that the crystal orientation relationship between the film and the substrate was TiC(001)//MgO(001) and TiC[100]//MgO[100]. Transmission electron microscopy and low energy electron diffraction were also used to verify the epitaxial growth of the films.

Deposition of titanium carbide films from mixed carbon and titanium plasma streams

Dual source metal plasma immersion ion implantation and deposition was used to deposit TixCy films over a wide range of Ti:C composition. This technique is well adapted for this purpose and allows one to tailor the microstructure and properties of the films. We investigated the variation of the composition, bonding states, and structure as functions of the deposition conditions. Excess carbon and contamination oxygen are incorporated in the TiC lattice interstitially and substitutionally, respectively. The wear mechanism of a stoichiometric TiC film was investigated and compared to that of a diamondlike carbon film. TiC fails by wear and microcrack propagation.

Growth of TiC films by thermal laser-assisted chemical vapour deposition

The kinetics in thermal laser-assisted chemical vapour deposition (LCVD) of titanium carbide (TiC) films and the influence of growth conditions on the structure and morphology of the deposits have been investigated. TiC spots were deposited onto silica substrates using a CW TEM00 CO2 laser beam. The reaction gas mixture consisted of TiCl4, CH4 and H2 and the ratios of the partial pressures of the reactants were varied. The films were analysed by X-ray diffractometry (XRD), micro-Raman spectroscopy, scanning electron microscopy (SEM) and profilometry.

Ｘ線材料強度 ＜１１０＞配向したＴｉＣ膜のＸ線応力測定

The investigation on the residual stress of titanium carbide films in terms of the X-ray diffraction method is our purpose. However, it is hard to measure the stress by the commonly used X-ray stress measurement, because the sin2ψ method demands macroscopic isotropy from the specimen but the ‹110› orientation is observed for our evaporated TiC film by CVD. Therefore, in this paper, the X-ray stress measurement for ‹110› oriented films was formulated by introducing the weighted average method for the crystallite orientation distribution. The formulation derived showed that the relation between the stress of the specimen and the measured strain by X-ray diffraction depended on the measured diffraction planes. Then, the stress calculation was made and discussed based on the loading experiments.

Room temperature deposition of titanium carbide by ion-beam-enhanced reaction of titanium films with hydrocarbons

In this study, titanium was deposited in an atmosphere of ethane and ethene by electron-beam evaporation onto various substrates at ambient temperature. During condensation, titanium was irradiated with argon ions of medium energy (12 keV) from an ion source. The composition of the resulting titanium carbide films was studied using Auger electron spectroscopy. The phase composition and crystal orientation were determined using X-ray diffraction. The results show that, by varying the ion current density, partial pressure and gaseous species, the composition of the titanium carbide films can be varied widely.

Laser reactive ablation deposition of TiC films

Titanium carbide films were deposited on silicon wafers by XeCl (308 nm) excimer laser ablation of titanium in low pressure (10 −6–10 −1 mbar) methane atmosphere. Series of 10000 pulses at the repetition rate of 8 Hz were directed to the target surface. The fluence was set at 4.5 and 5.5 J/cm 2. Pulse duration was about 30 ns. The deposited films were charcterized by different techniques (Rutherford backscattering spectrometry, X-ray diffractometry and scanning electron microscopy). Results show that at both fluences and at pressures below ≈ 10 −5 mbar the deposited films are mainly formed of metallic titanium. In the range 10 −3–10 −1 mbar, at the fluence of 4.5 J/cm 2, the deposits are formed of titanium carbide (TiC) with only traces of oxides. At the fluence of 5.5 J/cm 2 the amount of ablated material is too large to undergo complete reaction and mostly metallic titanium is deposited.

Laser reactive ablation deposition of titanium carbide films

Titanium carbide films were deposited on silicon wafers by XeCl (308 nm) excimer laser ablation of titanium in low pressure (10 −3 mbar) methane atmosphere. Series of 10 000 pulses at the repetition rate of 8 Hz were directed to the target surface. The fluence was set at about 5 J cm−2. Pulse duration was about 30 ns. The deposited films were characterized by different techniques (X-ray diffraction, scanning electron microscopy and Rutherford backscattering spectrometry).

Chemistry, microstructure, and electrical properties at interfaces between thin films of titanium and alpha (6H) silicon carbide (0001)

Epitaxial thin films (4–1000 Å) of Ti contacts have been deposited via UHV electron beam evaporation at room temperature on monocrystalline, n-type, alpha (6H)-SiC(0001). The interfacial chemistry and microstructure, and the electrical properties, were investigated at room temperature and after annealing at 700 °C up to 60 min. High resolution TEM analyses revealed the formation during annealing of reaction zones consisting of Ti5Si3 and TiC. The corresponding electrical properties exhibited considerable stability except after an initial 20 min anneal. Current-voltage (I-V) measurements showed that the Ti contacts were rectifying with low ideality factors (n < 1.09) and typical leakage currents of 5 × 10−7 A/cm2 at −10 V. The Schottky barrier heights calculated from x-ray photoelectron spectroscopy and I-V and V-V measurements were between 0.79 and 0.88 eV for the as-deposited contacts and between 0.86 and 1.04 eV for the annealed contacts.

Titanium Carbide Films Deposited by Laser Reactive Ablation

ABSTRACTTitanium carbide films were deposited on silicon wafers by laser reactive ablation. A pure titanium target placed inside a methane (CH4) atmosphere was irradiated by a XeCl excimer laser with a fluence of 5 J/cm2 and a repetition rate of 8 Hz. Experiments were performed at different values of the ambient pressure in order to investigate the influence of the deposition parameters on the film properties. Results show that at low pressure values (p< 10-5 mbar) the deposited layers are mainly constituted of metallic titanium whereas for pressure ranging from 10-5 to 10-1 mbar they are formed of titanium carbide (TiC) with small amount of oxides. The stoichiometry and thickness of the titanium carbide films can be controlled by the partial pressure of the atmosphere and the number of laser pulses, respectively.

Characteristics of hollow cathode discharge plasma and its application for the reactive ion plating of TiN and TiC

A hollow cathode discharge (HCD) plasma source was developed and its characteristics were investigated as the evaporation and ionization source for the reactive ion plating of titanium. There is a proper pressure range for ion plating process ∼1×10−2 mbar for the maximum electron density. Titanium nitride and titanium carbide films have been prepared by the HCD plasma enhanced reactive ion plating. The dependence of the electron density and temperature of plasma on the vessel pressure was examined. The interfacial region of the titanium-coated SUS-304 and the high-speed steel substrates were analyzed by the Auger electron spectroscopy depth profiling to identify the effects of the ion bombardment. It was shown that the parameters such as the substrate bias voltage and reactive gas flow rate influenced the film properties such as the crystal orientation, color tone, deposition rate, grain size, and hardness.

Production of Titanium Carbide Films by Reactive Ion Plating and Evaluation of Film Corrosion Resistance.

Transition metal carbide is expected to have a new application in the future as a corrosion resistant material against nonoxidizing acids. The purpose of this investigation is to evaluate the corrosion resistance of titanium carbide in sulfuric acid. For this purpose, titanium carbide films of various compositions were produced by reactive ion plating. The deposition rate and carbon content of the product films tended to increase with an increase in the flow rate of acetylene as a reactive gas at a constant electron beam current for evaporating titanium. The increase in the acetylene flow rate also led to great improvement in the corrosion resistance of the product films. The potential/current density curves showed that the maximum of the active dissolution current decreased exponentially with the rate increase in the range of 0-2.80×10–7 m3·s–1. The most corrosion resistant titanium carbide film, produced at 6.20×10–7 m3·s–1, has an extremely low current density, e.g., 3.6×10–4 A·m–2 at 0.5 V vs. Ag/AgCl, which is less that 1/5 000 of the titanium film current density. The corrosion of the titanium carbide film was apparently inhibited even in 1 kmol·m–3 H2SO4 at 373 K.

Tribological behavior of TiC thin films grown by pulsed laser deposition (PLD)

The tribological behavior of titanium carbide (TiC) thin films grown by excimer pulsed laser deposition (PLD) was investigated. The purpose of this work was to evaluate the effects of film deposition temperature, substrate hardness, and counterface hardness on the friction and wear behavior of the TiC films. Films were grown at room temperature (RT) and at 300 °C. Substrate hardness was varied by selecting the heat treatments of the 440C stainless steel (SS) disks; the counterface hardness was varied through materials selection ( e.g. hardened 440C SS and sapphire). Friction coefficients and wear lives were determined for each film/substrate/ counterface configuration. The wear surfaces were investigated by optical and scanning electron microscopy. The PLD TiC films grown at room temperature and 300 °C were stoichiometric and crystalline, with a grain size of 2–10 nm. The films displayed very good adherence in the wear tests, and their friction coefficients ranged from 0.2 to 0.4 against 440C SS and sapphire balls, which compares well with data of films grown with conventional methods. The wear life of the films deposited on annealed SS was lower than that for films deposited on tempered SS. Films deposited at RT showed a better wear resistance than films deposited at 300 °C, whereas the wear of the SS balls was lower in the tests with the films deposited at 300 °C. The impact of this work is: (i) hard, wear resistant TiC films can be deposited by PLD at temperatures as low as room temperature; and (ii) using PLD, the film deposition temperature can be used to control film properties.

Ion Bombardment Effect on the Hardness of Ti(C,N,O) Films Prepared by Ion Beam Controlled Deposition (IBCD)

Ion beam controlled deposition (IBCD) or ion beam assisted deposition (IB AD) of Ti(C,N,O) films has been investigated much in the last decade for both the advantage of this advanced technology and the promising properties of such materials. Ti(C,N,O) films are various solid solutions of interstitial compounds TiC, TiN and TiO of F.C.C structure with lattice constants lying between the values of the pure compounds. Some content of oxygen improves their wear resistance due to the lower fn;e enthalpies of such films in comparison with pure TiC and TiN films [1]. Many so-synthesizcd titanium carbide and titanium nitride films reported in published papers were actually of this sort as they often had more or less oxygen content from residual gas in vacuum. A number of papers were contributed to depict the texture and composition dependence of film on the arrival ratio of assisting ions versus deposited atoms (AR) as well as their mechanical properties [2–6]. However, the film formation mechanism in IBCD isn't quite clear yet, especially for cases with assisting ion energy of several to tens of keV. During a course to synthesize Ti(C,N,O) films by IBCD with the two beam technique, datum were accumulated. Based on a part of it, a previous paper on ion beam governed preferential growth in IBCD has been published [7]. This paper was aimed to search for the origin of ion bombardment effect on film hardness.

Coating of titanium carbide films on stainless steel by chemical vapour deposition and their corrosion behaviour in a Br2-O2-Ar atmosphere

Stainless steel (SUS304) plates were coated with TiC films using chemical vapour deposition (CVD) as a candidate material for “UT-3” which is a promising process of hydrogen production through the thermal decomposition of water. The corrosion behaviour of the TiC film-coated SUS304 plates was examined in a Br2-O2-Ar atmosphere. The effects of CVD conditions on the surface texture, deposition rates and preferred orientation of the TiC films were investigated, and the optimum CVD conditions determined. Corrosion of the TiC film-coated SUS304 plates in the Br2-O2-Ar atmosphere was mainly caused by oxidation of the TiC film and SUS304 substrate. Microcracks in the TiC films lead to corrosion of the SUS304 substrate. At oxygen partial pressures below 0.1 kPa, weight loss was observed due to the formation of volatile titanium and iron bromides. At oxygen partial pressures greater 0.1 kPa, the time dependence of weight increase was parabolic due to the formation of oxide scale. The oxide scales were mixtures of TiO2, Fe2O3 and Fe3O4. The corrosion mechanism is discussed thermodynamically.

Coating of titanium carbide films on stainless steel by chemical vapour deposition and their corrosion behaviour in a Br2-O2-Ar atmosphere

Coating of titanium carbide films on stainless steel by chemical vapour deposition and their corrosion behaviour in a Br2-O2-Ar atmosphere

Low Temperature Synthesis of Carbide Thin Films by Pulsed Laser Deposition (PLD)

ABSTRACTThin films of titanium carbide (TiC) and boron carbide (B4C) were grown by excimer pulsed laser deposition (PLD) at room temperature (RT) and 300°C. Films were deposited using the output of an excimer laser operating with KrF gas (γ = 248 nm, 15 ns pulse duration) to ablate hot-pressed targets. Film chemistry, morphology, and crystallinity were investigated. Stoichiometric, crystalline TiC films were grown on 440C stainless steel and NaCl substrates at room temperature and at 300°C. The films grown on NaCl were nanocrystalline, cubic TiC, with a grain size ranging between 2 and 10 nm in diameter. Boron carbide films were grown on silicon {100} substrates at room temperature and at 300°C. Film chemistry and stoichiometry duplicated that of the B4C target, which contained B4C and a mixed C-B-O-N binder phase. SEM analysis indicated that the morphology of the films was uniform, non-porous, and fine-grained. The films exhibited good adhesion and wear resistance, based on friction and wear data collected with a ball-on-disc tribometer.

Low Temperature Synthesis of Carbide Thin Films by Pulsed Laser Deposition (Pld)

AbstractThin films of titanium carbide (TiC) and boron carbide (B4C) were grown by excimer pulsed laser deposition (PLD) at room temperature (RT) and 300°C. Films were deposited using the output of an excimer laser operating with KrF gas (λ = 248 nm, 15 ns pulse duration) to ablate hot-pressed targets. Film chemistry, morphology, and crystallinity were investigated. Stoichiometric, crystalline TiC films were grown on 440C stainless steel and NaCl substrates at room temperature and at 300°C. The films grown on NaCI were nanocrystallinc, cubic TiC, with a grain size ranging between 2 and 10 nm in diameter. Boron carbide films were grown on silicon {100} substrates at room temperature and at 300°C. Film chemistry and stoichiometry duplicated that of the B4C target, which contained B4C and a mixed C-B-O-N binder phase. SEM analysis indicated that the morphology of the films was uniform, nonporous, and fine-grained. The films exhibited good adhesion and wear resistance, based on friction and wear data collected with a ball-on-disc tribometer.

Corrosion properties of TiC films prepared by activated reactive evaporation

Potentiodynamic measurements were used to test the corrosion properties of titanium carbide (TiC) films. The films were deposited by the activated reactive evaporation process which consists of electron beam evaporating titanium at a rate of 0.22 g min -1 in the presence of a d.c. discharge of C 2H 2. Pressure was maintained at 1 × 10 -3 Torr during deposition. The films were deposited onto quartz substrates held at 400 °C. By growing films on an insulating substrate the inherent corrosion properties of TiC films without any substrate contribution can be evaluated. The thickness and grain size of the films, which had a slight (111) texture, were 4 μm and 2 - 3 μm respectively. The TiC films were highly corrosion resistant. Activity in the polarization curve was obtained only in a strong electrolyte (1 M HCl). Neither sulphuric nor perchloric acid could activate the film. The passivation potential and critical current density (current density at the passivation potential) in 1 M HCl were 710 mV ( vs. the saturated calomel electrode (SCE)) and 60 μA cm -2 respectively. The passive potential and passive current density were 900 mV (SCE) and 20 μA cm -2 respectively. The passive potential range was 900 mV up to at least 6000 mV (SCE). The oxygen overpotential was high (more than 5000 mV) for the TiC film and comparable with that for titanium.