Titanium Nitride Films Research Articles

Investigation of FeN and TiN thin films properties for possible application in electronic devices

In the present work, thin films of FeN (Iron Nitride) and TiN (Titanium Nitride) were deposited in samples of laminated glass by cathodic cage deposition technique using stainless steel and titanium cages, respectively. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Wettability and Electrical Conductivity techniques were used to characterize the samples. To obtain the electrical conductivity values, the electrical resistivity (also known as specific electrical resistance) was calculated. In this way, the lower the resistivity, the easier is the passage of an electric charge through the material. To this purpose, it was used the four-point probes method. FeN film presented hydrophobic surface, and TiN film hydrophilic surface. Both films were promising in electrical conductivity analysis. The results show promise applications in the electronic devices.

Superior-performance TiN films sputtered for capacitor electrodes

Titanium nitride (TiN) thin films were deposited on Si (100) substrate by direct current reactive sputtering without and with the application of a substrate bias. The aim of this work was to clarify the effects of substrate bias on film properties systematically. The results showed that the substrate bias process changed the film growth regime, and therefore, the stoichiometry, crystalline orientation and morphology were completely different from those of the films prepared without a substrate bias. Importantly, the application of substrate bias contributed a reduction in the resistivity from 100 to 31 μΩ cm, an increase in density by 12% and a decrease in RMS roughness to less than 1 nm. In addition, a significant reduction in leakage current density was observed for capacitors using TiN top electrode deposited with substrate bias.

Hydrogen-Assisted Sputtering Growth of TiN on Ceramic Substrates

Titanium nitride (TiN) has mechanical and electrical characteristics applicable for very large scale integration (VLSI) and discrete electronic devices. This study assessed the effect of hydrogen on sputtering growth of TiN on ceramic substrates. Although ceramic substrate is used in discrete device applications due to its insulating property, ceramic is also porous and contains oxygen and water vapor gases, which can be incorporated into TiN films during growth. In addition, discrete devices are usually packaged in glass sealing at 700 °C, and reaction with the trapped gases can significantly degrade the quality of the TiN film. In order to evaluate ways to minimize the effects of these gases on TiN, hydrogen gas was introduced during sputtering growth. The main hypothesis was that the hydrogen gas would react with oxygen to lower the oxygen density in the vacuum chamber, which would suppress the effects of the trapped gases in the ceramic and ultimately improve the quality of the TiN film. Improvements in TiN quality were confirmed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and resistance measurements. During the glass-sealing process, N2-purging at 400 °C was effective at keeping the TiN in a low resistance state. These results show that introducing hydrogen gas during sputtering growth could solve the problems caused by ceramic substrates.

Synthesis of AuAg@Ag core/shell bimetallic nanoparticles in titanium nitride thin films by sequential ion implantation

In this study, we demonstrated the formation of a new type of AuAg@Ag nanostructure in titanium nitride (TiN) thin films using sequential implantation of Au and Ag ions. The TiN films deposited by DC reactive sputtering were sequentially implanted with 200 keV gold ions at fluences of 0.5 × 1016 and 1 × 1016 ions/cm2 and 150 keV silver ions at fluences of 1 × 1016, 2 × 1016, 3 × 1016, and 4 × 1016 ions/cm2. Formation of spherical-like particles with dimensions below 10 nm, homogeneously distributed along the ion track of implanted ions is verified by high resolution transmission electron microscopy. Specific nanostructure containing AuAg alloy in the center of the particle and only silver on the periphery was found in the TiN sample sequentially implanted with 1.0 × 1016 ions/cm2 of Au and 4 × 1016 ions/cm2 of Ag using high angle annular dark field scanning electron microscopy together with elemental mapping analysis. On the other hand, for the sample implanted with 0.5 × 1016 ions/cm2 of Au and 4 × 1016 ions/cm2 of Ag only formation of AuAg alloy was observed. A mechanism for the formation of a new type core/shell nanostructure in ion implanted TiN thin films is proposed. By varying the implantation fluence of the gold and silver ions properly, the optimized experimental parameters for creation of a specific AuAg@Ag core/shell nanoparticles were achieved.

Microelectrode Array With Transparent ALD TiN Electrodes.

Low noise platinum black or sputtered titanium nitride (TiN) microelectrodes are typically used for recording electrical activity of neuronal or cardiac cell cultures. Opaque electrodes and tracks, however, hinder the visibility of the cells when imaged with inverted microscope, which is the standard method of imaging cells plated on microelectrode array (MEA). Even though transparent indium tin oxide (ITO) electrodes exist, they cannot compete in impedance and noise performance with above-mentioned opaque counterparts. In this work, we propose atomic layer deposition (ALD) as the method to deposit TiN electrodes and tracks which are thin enough (25–65 nm) to be transparent (transmission ∼18–45%), but still benefit from the columnar structure of TiN, which is the key element to decrease noise and impedance of the electrodes. For ALD TiN electrodes (diameter 30 μm) impedances from 510 to 590 kΩ were measured at 1 kHz, which is less than the impedance of bare ITO electrodes. Human induced pluripotent stem cell (hiPSC)-derived cortical neurons were cultured on the ALD TiN MEAs for 14 days without observing any biocompatibility issues, and spontaneous electrical activity of the neurons was recorded successfully. The results show that transparent ALD TiN film is a suitable electrode material for producing functional MEAs.

Development of transmon qubits solely from optical lithography on 300 mm wafers

Qubit information processors are increasing in footprint but currently rely on e-beam lithography for patterning the required Josephson junctions (JJs). Advanced optical lithography is an alternative patterning method, and we report on the development of transmon qubits patterned solely with optical lithography. The lithography uses 193 nm wavelength exposure and 300 mm large silicon wafers. Qubits and arrays of evaluation JJs were patterned with process control which resulted in narrow feature distributions: a standard deviation of 0.78% for a 220 nm linewidth pattern realized across over half the width of the wafers. Room temperature evaluation found a 2.8%–3.6% standard deviation in JJ resistance in completed chips. The qubits used aluminum and titanium nitride films on silicon substrates without substantial silicon etching. T1 times of the qubits were extracted at 26–27 μs, indicating a low level of material-based qubit defects. This study shows that large wafer optical lithography on silicon is adequate for high-quality transmon qubits, and shows a promising path for improving many-qubit processors.

Plasma-Enhanced Atomic Layer Deposition of TiAlN: Compositional and Optoelectronic Tunability.

Titanium nitride (TiN) is a unique refractory plasmonic material, the nanocomposites and alloys of which provide further opportunities to tailor its optical and photonic properties. We prepare TiAlN films of continuously variable compositions through the systematic variation of TiN versus AlN cycle ratio in plasma-enhanced atomic layer deposition (PEALD) and investigate the resulting thin-film composition, crystallinity, and optical properties. The resulting properties of TiAlN films are not simple linear combinations of the TiN and AlN films, which exhibit distinct metallic and dielectric properties, but instead are dramatically influenced by the local chemical environment of neighboring constituents. In situ spectroscopic ellipsometry further enables measurement of the varying optical properties of TiAlN films, which evolve over 10 s of nm of film thickness. The tunable optoelectronic properties of TiAlN films enable durable coatings of variable electrical resistance as well as high-temperature diffusion barriers and optical coatings with application to selective solar absorbers and emitters.

Effect of buffer layer nature on multiwall carbon nanotube growth rate by PECVD

In this work, vertically aligned multiwall carbon nanotubes (MWCNTs) were produced, at 600 °C, by plasma enhanced chemical vapour deposition (PECVD), in an electron cyclotron resonance (ECR) plasma chamber using a C2H2/NH3 gas mixture. The MWCNTs were directly grown onto a carbon buffer thin film (a-C) or a titanium nitride film (TiN) deposited on a silicon surface. For this purpose, nickel (Ni) nanoparticles were deposited on the both buffer layers, by an electrochemical procedure, and used as a catalyst for the MWCNT growth. The effect of the buffer layer on MWCNT growth rate during different growth times was investigated in this work. It was found that MWCNT produced over the a-C buffer grow faster compared with those grown over the TiN buffer. Moreover, when the growth time increases, the MWCNTs deposited on the a-C buffer can maintain a relatively high density compared with those grown on the TiN layer. Using in-situ X-ray photoelectron spectroscopy, the effect of both buffers on the MWCNT growth rate is discussed with reference to changes in the state of Ni catalysts annealed at 600 °C. The results demonstrate the benefit of using the a-C layer for MWCNT grown by PECVD for specific applications including electrochemical biosensors and electrochemical capacitors.

Effect of bias on structure mechanical properties and corrosion resistance of TiNx films prepared by ion source assisted magnetron sputtering

Titanium nitride (TiNx) films were deposited on 304 stainless steel and silicon (100) wafers by ion source assisted magnetron sputtering. The effect of substrate bias voltage on the preparation and properties of TiNx films was investigated. The results show that as the substrate bias voltage increases from 0 V to −400 V, the deposition rate of TiNx film decreases significantly and the density increases, which can be attributed to the re-sputtering effect at high ion bombardment. The texture of TiNx films varies gradually from (111) to (200) with the increase of energy delivered into the growing film. The hardness of the film deposited under −200 V bias voltage reaches the maximum value, 12.9 GPa. Meanwhile, the toughness and corrosion resistance of the film reach a maximum at a bias voltage of −400 V. In conclusion, the density, hardness, toughness and corrosion resistance of TiNx films can be increased by changing the substrate bias voltage.

One-step sputtered titanium nitride nano-pyramid thin electrodes for symmetric super-capacitor device

Thin films of nano-pyramid titanium nitride (TiN) were sputtered on 304L steel substrate using DC magnetron reactive sputtering. The symmetric full-cell supercapacitor delivered the typical capacitance of 112 F/g at a current density of 1 A/g and retained 30 F/g at high current density of 20 A/g. The device can be charged and discharged for 30,000 cycles with 92.6% capacitance retained.

Mitigating the electron cloud effect in the SuperKEKB positron ring

SuperKEKB is an electron-positron collider with asymmetric energies located at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. After more than five years of upgrading work on KEKB, phase-1 commissioning commenced in February 2016 and ended in June of the same year. Following a 20-month shutdown for the installation of a particle detector, BELLE II, phase-2 commissioning commenced in March 2018 and ended in July of the same year. This paper describes one major issue faced by SuperKEKB: the electron cloud effect (ECE) in the positron ring, which was observed during phase-1 commissioning. In the high-beam-current region, electron clouds, i.e., the source of the ECE, existed in the beam pipes at drift spaces of the ring, which had antechambers and a titanium nitride (TiN) film coating as countermeasures against the ECE. Permanent magnets and solenoids used to generate magnetic fields in the beam direction were attached to the beam pipes as additional countermeasures before the next commissioning phase commenced. Consequently, during phase-2 commissioning, experiments showed that the threshold of the current linear density for exciting the ECE increased by a factor of at least 2 compared to that during phase-1 commissioning. While the countermeasures were strengthened, the effectiveness of the antechambers and TiN film coating of the real beam pipe was reevaluated. Through various simulations and dedicated experiments during phase-2 commissioning, the antechambers were found to be less effective than anticipated with regard to reducing the number of photoelectrons in the beam channel. In contrast, the TiN film coating had a low secondary electron yield, as expected.

Bioapplication of TiN thin films deposited using high power impulse magnetron sputtering

Titanium nitride (TiN) has been deposited on TiAl6V4 using a reactive high-power impulse magnetron sputtering (HiPIMS) deposition technique and investigated for use as a bio-coating. During HiPIMS deposition, the peak current of the Ti target was varied from 75 to 175 A through adjusting the frequency from 200 to 100 Hz. Plasma diagnosis shows that, as compared to DC sputtering deposition process, all the peak currents and maximum powers are higher in the HiPIMS deposition process. The high peak current and maximum power in the HiPIMS process help the ionization of the sputtered Ti and also increase the amount of N2+ species in the plasma, hence leading to a high N/Ti ratio of the TiN film. Therefore, the resulting TiN exhibits great corrosion resistance in simulated bodily fluid and shows excellent cell viability against the osteoblast-like MG-63 cells among other TiN samples.

Comparison of TiN and CNx coatings on orthodontic stainless steel: Tribological and biological evaluation

Surface modification of orthodontic appliance materials has contributed to the development and popularization of orthodontic treatment. Important characteristics of modified materials include the coefficient of friction, antimicrobial activity, and biocompatibility. To investigate these characteristics, we coated a stainless steel (SS) substrate, which is used to manufacture orthodontic appliances, with a titanium nitride (TiN) or carbon nitride (CNx) film. The coating thickness, elements, and surface morphology were characterized by scanning electron microscopy and energy-dispersive spectrometry. The coefficient of friction was measured using a universal micro-tribotester; the density of Streptococcus mutans was used to assess antimicrobial ability; and the viability of human periodontal ligament fibroblasts implanted on the samples was used to evaluate the biocompatibility of the different films. We found that the CNx film exhibited a lower friction force, effective antimicrobial activity, and favorable biocompatibility compared to the uncoated and TiN-coated SS. In conclusion, a CNx film is promising for modifying archwires to decrease friction and improve antimicrobial activity and biocompatibility.

Modulating phase by metasurfaces with gated ultra-thin TiN films.

Active control over the flow of light is highly desirable because of its applicability to information processing, telecommunication, and spectroscopic imaging. In this paper, by employing the tunability of carrier density in a 1 nm titanium nitride (TiN) film, we numerically demonstrate deep phase modulation (PM) in an electrically tunable gold strip/TiN film hybrid metasurface. A 337° PM is achieved at 1.550 μm with a 3% carrier density change in the TiN film. We also demonstrate that a continuous 180° PM can be realized at 1.537 μm by applying a realistic experiment-based gate voltage bias and continuously changing the carrier density in the TiN film. The proposed design of active metasurfaces capable of deep PM near the wavelength of 1.550 μm has considerable potential in active beam steering, dynamic hologram generation, and flat photonic devices with reconfigurable functionalities.

Experimental-numerical Technique to Evaluate the Thickness of TiN Thin Film

In this study, the numerical analysis of instrumented indentation testing was combined with the experimental procedure to evaluate the mechanical properties and thickness of a titanium nitride (TiN) film deposited on titanium substrate (Ti) by plasma processing. TiN film thickness is an important parameter for the surface treatment industry. In numerical analysis, the finite elements method (FEM) was applied using Marc™ commercial software. Initially, the mechanical properties of the film and substrate were determined using a numerical-experimental methodology, combining the results of indentation testing with a Berkovich indenter and the same numerical simulation for both the film and substrate. Next, the behavior of instrumented Vickers hardness as a function of maximum indenter penetration depth (hmax) was compared with the numerical results of this hardness as a function of the ratio between penetration depth and film thickness (hmax/t). Both curves were fitted using power law equations, which calculated film thickness applying a new convergence algorithm. Finally, it also was shown that the film thickness obtained agrees with the experimental range reported in the literature.

Chemical vapor deposition of titanium nitride thin films: kinetics and experiments

Titanium nitride (TiN) films were grown by chemical vapor deposition (CVD) from titanium chlorides, ammonia (NH3) and hydrogen (H2) on single crystal c-plane sapphire, WC–Co, stainless steel and amorphous graphite substrates. The preferred orientation and color of TiN layer are studied by combining a simplified kinetic model with experiments.

Optimization of Titanium Nitride Film Synthesis: Correlations Between the Structure / Micro-Hardness and Deposition Conditions

Optimization of Titanium Nitride Film Synthesis: Correlations Between the Structure / Micro-Hardness and Deposition Conditions

Modeling of thermal processes in magnetrons with single hot target and “sandwich-target”

The present work studies thermal processes in DC magnetron sputtering units. A unit with a single hot titanium target is used to deposit films of titanium and titanium nitride. Another sputtering unit called “sandwich-target” is used to deposit films of Cr – Ti or CrN – TiN solid solutions. The sandwich-target consists of a cold chromium target and a hot titanium slotted target located on the same axis. Thermal processes are presented in the form of a stationary heat problem with a surface source of constant power using a three-dimensional homogeneous Fourier equation. The tasks in both cases were solved numerically using the Heat Transfer Module of the COMSOL Multiphysics package. In order to set the boundary conditions, 3D models of the sputtering units were developed. The distributions of the heated elements' surface temperatures were determined. The modeling results were compared with the experimental results. The study found that the influence of the thickness and discharge power on the effective surface temperature of hot elements is nonlinear. In the experimental region, it can be adequately described by a second degree polynomial. The problem-solving method and the developed 3D models are universal and, with the necessary adjustment, can be used to study magnetrons with any metal targets.

Enhanced Visible Light Sensitization of N-Doped TiO2 Nanotubes Containing Ti-Oxynitride Species Fabricated via Electrochemical Anodization of Titanium Nitride

The concentration and chemical state of nitrogen represent critical factors to control the band-gap narrowing and the enhancement of visible light harvesting in nitrogen-doped titanium dioxide. In this study, photocatalytic TiO2–N nanoporous structures were fabricated by the electrochemical anodization of titanium nitride sputtered films. Doping was straightforwardly obtained by oxidizing as-sputtered titanium nitride films containing N-metal bonds varying from 7.3 to 18.5% in the Ti matrix. Severe morphological variations into the as-anodized substrates were registered at different nitrogen concentrations and studied by small-angle X-ray scattering. Titanium nitride films with minimum N content of 6.2 atom % N led to a quasi-nanotubular geometry, whereas an increase in N concentration up to 23.8 atom % determined an inhomogeneous, polydispersed distribution of nanotube apertures. The chemical state of nitrogen in the TiO2 matrix was investigated by X-ray photoelectron spectroscopy depth profile analysis ...

Corrosion resistance and cytotoxicity studies of DLC, TiN and TiCN films coated on 316L stainless steel

Corrosion resistance and cytotoxicity of diamond-like carbon (DLC), titanium nitride (TiN) and titanium carbo-nitride (TiCN) films coated on AISI 316L grade stainless steel were investigated. All films were deposited on the stainless steel substrates using a cathodic arc plasma deposition-physical vapor deposition (PVD) technique. Film compositions were measured using energy dispersive X-ray spectroscopy (EDS). Contact angle was measured using contact angle measurement. Corrosion resistance was determined using potentiodynamic polarization. Cell viability was analysed using cytotoxicity test. The results show that all films are more hydrophilic (80.75° to 87.79°) than uncoated stainless steel sample (96.63°). Moreover, TiCN, DLC and TiN films have good potential corrosion resistance values of -0.353 V, -0.58 V and -0.68 V, respectively. This is due to the formation of titanium carbides and the sp3 sites structure of DLC film. Meanwhile, DLC film appears to be the most biocompatible with the highest cell viability of 104%.