TiN Thin Films Research Articles

Use of ball-cratering wear test and nanoscratching test to compare the wear resistance of homogeneous and functionally graded titanium nitride thin films

Homogeneous (HM) and functionally graded (FG) TiN thin films were produced by the grid-assisted magnetron sputtering (GAMS) technique. The joint use of ball-cratering micro-abrasive wear test (BCMA) and nanoscratching (NN) test was proposed and carried out to evaluate the wear resistance of TiN films. The results showed an increase of 33.3% wear resistance in the FG TiN thin film, when compared with the HM TiN thin film. This result was justified by the higher resistance to nucleation and propagation of cracks and higher level of adhesion to the substrate by the FG TiN thin film, validated through the NN tests.

Study of electronic, structural and magnetic properties of electrodeposited Co2MnSn Heusler alloy thin films

Spintronics is the new emerging field that recasts the modern information technology using electron spin along with its charge. Various spintronic devices have been under research for the last few years such as GMR based devices, MRAMs, etc. These devices are based on the conventional ferromagnetic materials that exhibit spin asymmetry. Half metallic ferromagnetic materials, especially Heusler alloys, are considered as most promising candidates because of high spin polarization. Previously, Heusler alloys have been investigated theoretically. Few experimental reports are available that belong to high-cost vacuum-based methods. Furthermore, detailed magnetic study at room temperature is rare to be found. In this research work, structural, electronic and magnetic properties of Co2MnSn Full Heusler alloy are investigated experimentally and through density functional theory by ADF. Theoretical results of this study predict the half metallic and asymmetric behavior of the Co2MnSn Full Heusler alloy with L21 structure. The cobalt manganese tin thin films are prepared by the electrodeposition method by varying applied reducing potential from 1 to 2 V. Mixed phases are observed at an applied potential ranging from 1 V to 1.5 V. Co2MnSn phase of full Heusler alloy is observed at an applied voltage of 1.75 V. Further increase in applied voltage to 2 V results in strengthening and stability of Co2MnSn phase. Magnetic moment μB of 4.10 is in close agreement to the one calculated by Slater-Pauling Rule for full Heusler alloys. The M−H loops of cobalt manganese tin Heusler alloy electrodeposited thin films exhibit soft ferromagnetic behavior. Arrott plots show the ferromagnetic nature of cobalt manganese tin electrodeposited thin films by exhibiting convex shape. MH curves show variation in exchange bias with varying the applied potential.

Thin films of Titanium Nitride deposite on substrates used for biomedical applications

In the present work, thin films of TiN were obtained on AISI 316L stainless steel substrates by DC unbalanced magnetron sputtering with promising characteristics such as resistance to wear and corrosion to be used in biomedical applications by changing the temperature of the substrate and the mixture. of gases. Microstructural characterization was performed using optical microscopy, atomic force microscopy, and scanning electron microscopy (SEM). Scratch tests were performed using an irradiated and non-irradiated ultra-high molecular weight polyethylene (UHMWPE) pin on the coated and uncoated substrates to study and compare the scratch effect, continuing the same circumferential geometry, a stroke length of 200 m and a 5N wet load using pure Milli-Q water (type 1) to simulate body fluids with the pin to test its performance and implant durability showing higher values in the coefficient of friction (COF) in the TiN-coated samples.

Versatile Micro and Nano Patterning Technique for TiO2 and TiN‐Based Sol–Gel Thin Films

AbstractThis paper describes a tailored and versatile technology route to achieve micro and nanopatterning of both TiO2 and TiN thin films using a direct photo patternable sol–gel approach combined with a rapid thermal annealing and nitridation process. The approach consists in multi‐scale structuring TiO2 using laser direct writing or mask/colloidal lithography on a wide range of substrates including materials and of diverse geometry. These patterned TiO2 layers can subsequently be converted into a micro‐structured metallic TiN layer using a direct rapid thermal nitridation process that results in metallic thin films (TiN). This work demonstrates the versatility of this complete chain of soft chemistry based new process for patterning TiO2 and TiN thin films thereby avoiding expensive processes such as etching and lift‐off, while preserving their diffractive properties and high thermal stability, that is, up to 1000 °C under vacuum. The process is compatible with different kinds of substrates of different shapes and sizes. These results pave the way for developing a cost‐effective and time‐saving approach to different cutting‐edge applications such as metasurfaces, sensors, and applications in the luxury and decoration sector.

A Multimodal Sensing Device for Simultaneous Measurement of Dissolved Oxygen and Hydrogen Ions by Monolithic Integration of FET-Based Sensors.

We examined the possibility of measuring dissolved oxygen by using a potentiometric solid-state semiconductor sensor. Thin films of tin (IV) oxide (SnO2) are widely used in oxygen gas sensors. However, their ability to detect dissolved oxygen (DO) in solutions is still unknown. In this paper, we present a method for investigating the dissolved oxygen-sensing properties of SnO2 thin films in solutions by fabricating a SnO2-gate field-effect transistor (FET). A similarly structured hydrogen ion-sensitive silicon nitride (Si3N4)-gate FET was fabricated using the same method. The transfer characteristics and sensitivities were experimentally obtained and compared. The transfer characteristics of the FET show a shift in threshold voltage in response to a decrease in DO concentration. The SnO2-gate FET exhibited a sensitivity of 4 mV/ppm, whereas the Si3N4-gate FET showed no response to DO. Although the SnO2-gate FET responds to pH changes in the solution, this sensitivity issue can be eliminated by using a Si3N4-gate FET, which is capable of selectively sensing hydrogen ions without DO sensitivity. The experimental results indicate the promising properties of SnO2 thin films for multimodal sensing applications.

Suppressing Bulk and Interfacial Recombination Losses in Sn–Pb Perovskites for Efficient Printable Low‐Bandgap Photovoltaic Devices

Thin films of tin–lead alloyed perovskites are drawing growing attention, mainly owing to their tunable bandgaps in delivering efficient single‐ and multi‐junction photovoltaic devices. The rapid efficiency advancement of Sn–Pb perovskite devices has been dependent primarily on improving the crystal quality of perovskite films via retarding oxidation of Sn2+. Herein, it is demonstrated that in addition to obtaining high‐quality Sn–Pb perovskite thin films, reducing nonradiative recombination losses at interfaces is equally important for realizing efficient solar cells. An aromatic amine is first introduced to passivate the grain boundary in printed Sn–Pb perovskite films, which boosts the open‐circuit voltage (V OC) of the solar devices from 700 to 766 mV. Further enhancement of the V OC to 814 mV and finally to 837 mV is realized by forming a 2D/3D‐layered heterojunction and doping the hole extraction layer with a polyelectrolyte, respectively, benefiting from the largely suppressed nonradiative recombination losses at interfaces. Eventually, the mixed Sn–Pb perovskite devices with a bandgap of ≈1.27 eV yield a high efficiency of 19.06% and in parallel show improved shelf and light‐soaking stability.

Atomistic kinetic Monte Carlo simulation on atomic layer deposition of TiN thin film

The atomic layer deposition (ALD) process of TiN thin films is widely used in microelectronics, but the detailed growth mechanism is still elusive at the atomistic level. In the present computational study, we carry out kinetic Monte Carlo (kMC) simulations on the ALD process using TiCl4 and NH3 precursors. Based on the on-lattice model, we sort out key reactions relevant for the ALD process such as adsorption/desorption of precursors, generation of surface Cl atoms, and evolution of free HCl and Cl2 molecules. The reaction energies considering local environments are calculated at the level of density functional theory (DFT) while the activation barriers are linearly fitted to sampled cases among distinct reaction families. The resulting kMC model produces the temperature-dependent growth rates and the amounts of Cl residues in reasonable agreement with experiments. The detailed growth pathway is discussed based on the simulation results, which underscores the critical role of surface Cl atoms in the ALD process by generating HCl gas molecules. By revealing the atomistic mechanisms in the TiN-ALD process, the present work would help optimize material properties of TiN thin films.

Synergistic Effect of Anti‐Solvent and Component Engineering for Effective Passivation to Attain Highly Stable Perovskite Solar Cells

Defect passivation is a crucial process for achieving high‐performance perovskite solar cells (PSCs). Herein, the synergistic effect of anti‐solvent and component engineering for effective passivation to attain highly stable PSCs is demonstrated, specifically, for ethyl acetate as the anti‐solvent and CsBr as the additive in the MAPbI3 precursor solution. It is found that the rapid solvent evaporation results in fast nucleation, and the CsBr assists the perovskite grain growth. The synergistic effect of anti‐solvent and additive engineering leads to increased perovskite grain size, reduced defect density, improved quality of the perovskite thin film, and finally, enhanced efficiency and stability of the indium tin oxide/SnO2/perovskite/carbon device. The influence of this synergistic effect on the morphology and photovoltaic performance is systematically investigated. Printable PSCs with hole‐transport‐layer‐free carbon electrodes are designed and constructed, which achieve a champion photoelectric conversion efficiency of 16.45%, fill factor of 72.63%, short circuit current of 19.90 mA cm−2, and open circuit voltage of 1.14 V. Herein, a facile and low‐cost approach is demonstrated to obtain highly stable C‐PSCs and a promising strategy for future commercial application is provided.

Model-independent determination of the gap function of nearly localized superconductors

The gap function $\mathrm{\ensuremath{\Delta}}(\ensuremath{\omega})$ carries essential information on both, the pairing glue as well as the pair-breaking processes in a superconductor. Unfortunately, in nearly localized superconductors with a nonconstant density of states in the normal state, the standard procedure for extraction of $\mathrm{\ensuremath{\Delta}}(\ensuremath{\omega})$ cannot be applied. Here we introduce a model-independent method that makes it possible to extract $\mathrm{\ensuremath{\Delta}}(\ensuremath{\omega})$ also in this case. The feasibility of the procedure is demonstrated on the tunneling data for the disordered thin films of TiN. We find an unconventional feature of $\mathrm{\ensuremath{\Delta}}(\ensuremath{\omega})$ which suggests that the electrons in TiN are coupled to a very soft pair-breaking mode.

Comparison of quantitative elemental depth distribution analyses of Ni and Ti in co-sputtered Ni-Ti alloy thin films using MCs+ and M+ secondary ions

Compositional uniformity in Ni-Ti thin alloy films, both at the surface and in the depth, significantly enhances their performance in various engineering applications. Quantitative depth distributions of Ni and Ti in magnetron co-sputtered Ni-Ti thin alloy films of various composition and thickness, were determined through an effective depth profiling technique. Secondary ion mass spectrometry (SIMS) was utilized to determine the qualitative elemental depth distribution of Ni and Ti in the films using MCs+-SIMS (Cs+ primary ion beam; MCs+ secondary ions, 'M' is the element of interest) and M+-SIMS (O2+ primary ion beam) approaches. The qualitative depth profiles were converted to quantitative depth profiles using the relative sensitivity factor values determined from the elemental concentrations obtained through energy dispersive x-ray spectroscopy analysis of one of the Ni-Ti thin film taken as reference. Thickness of the deposited films determined by x-ray reflectivity was used for depth scale calibration of SIMS raw profile. A comparison of the analytical capabilities of MCs+-SIMS and M+-SIMS approaches for determining the mean concentration and quantitative depth distribution of elements Ni and Ti in deposited Ni-Ti thin films has been presented.

Structural evolution and thermal stability of functionally graded NiTi nano-glass thin films alloys during crystallization

Functionally graded and composite materials are known as new materials, which exhibit higher performances and provide a comprehensive application. This paper introduces a bi-layer Ni-rich/NiTiCu alloy with a composite structure comprising nano-crystal, glassy and amorphous microstructure. The successive crystallization of amorphous Ni-rich/NiTiCu bi-layer thin films deposited at room temperature was studied by annealing at 773 K for 15, 30, and 60 min. Different experiments, including scanning electron microscopy (SEM), grazing incidence X-ray diffraction (GIXRD), high-resolution transmission electron microscopy (HRTEM), and thermodynamics calculations (CALPHAD) were conducted to analyze the microstructure. The crystal nucleation, glassy/amorphous thermal stability against alloying elements, and related interfaces were studied. The as-deposited thin films were fully amorphous and had a rounded nano-glassy structure. HRTEM images indicated no long-range periodic lattice and the interface between layers was flat and sharp. Short-time annealing depicts non-spherical crystal nuclei in the amorphous NiTiCu layer with a diffuse interface. In contrast, after 60 min annealing, the NiTiCu and NiTi layers were fully and mostly crystallized with different structures, respectively. The results confirm the higher thermal stability of the amorphous NiTi binary alloy. Thermodynamic and diffusion studies indicate that the higher driving force of amorphous to B2 ordered structure against Cu addition along with the higher Cu diffusivity compared with Ni and Ti are responsible for lower thermal stability of NiTiCu. • The NiTi/NiTiCu bi-layer thin films deposited at RT on a Si substrate using DC magnetron. • The crystallization of amorphous bi-layer thin films was studied at different annealing at conditions. • The structure of the thin film and interface of the layers strongly depended on the composition andthe annealing conditions. • The amorphous NiTi thin film was more stable than the NiTiCu thin film as supported by thermodynamic calculation.

Tribomechanical and microstructural properties of cathodic arc-deposited ternary nitride coatings

Sintered carbides are promising materials for surfaces that are exposed to extreme wear. Owing to their high service load, ceramic-based thin films are coated on carbides using different techniques. In this study, non-toxic and cobalt-free powder metallurgy-sintered carbide samples were coated with TiN, TiAlN, CrAlN, and TiSiN ceramic-based thin film coatings by cathodic arc physical vapor deposition. The microstructure (phase formation, coating thickness, surface roughness, and topography), mechanical properties (hardness, modulus of elasticity, and plasticity indices), and tribological properties (nanoscratch and wear behavior) of the thin film coatings were investigated. No cracks or defects were detected in these layers. The ceramic-based ternary nitride thin film coatings exhibited better mechanical performance than the TiN coating. The TiN thin film coating had the highest average surface roughness, which deteriorated its tribological performance. The ternary nitride thin film coatings exhibited high toughness, while the TiN thin film coating exhibited brittle behavior under applied loads when subjected to nanoscratch tests. The wear resistance of the ternary nitride coatings increased by nearly 9–17 times as compared to that of the TiN coating and substrate. Among all the samples investigated, the substrate showed the highest coefficient of friction (COF), while the TiSiN coating exhibited the lowest COF. The TiSiN thin film coating showed improved mechanical and tribological properties as compared to other binary and ternary nitride thin film coatings.

Electrochemical Properties of Multilayered Sn/TiNi Shape-Memory-Alloy Thin-Film Electrodes for High-Performance Anodes in Li-Ion Batteries.

Sn is a promising candidate anode material with a high theoretical capacity (994 mAh/g). However, the drastic structural changes of Sn particles caused by their pulverization and aggregation during charge–discharge cycling reduce their capacity over time. To overcome this, a TiNi shape memory alloy (SMA) was introduced as a buffer matrix. Sn/TiNi SMA multilayer thin films were deposited on Cu foil using a DC magnetron sputtering system. When the TiNi alloy was employed at the bottom of a Sn thin film, it did not adequately buffer the volume changes and internal stress of Sn, and stress absorption was not evident. However, an electrode with an additional top layer of room-temperature-deposition TiNi (TiNi(RT)) lost capacity much more slowly than the Sn or Sn/TiNi electrodes, retaining 50% capacity up to 40 cycles. Moreover, the charge-transfer resistance decreased from 318.1 Ω after one cycle to 246.1 Ω after twenty. The improved cycle performance indicates that the TiNi(RT) and TiNi-alloy thin films overall held the Sn thin film. The structure was changed so that Li and Sn reacted well; the stress-absorption effect was observed in the TiNi SMA thin films.

Characteristics of TiN Thin Films Deposited by Substrate Temperature Variables Using Scanning Acoustic Microscopy

In this study, TiN thin films fabricated based on the substrate temperature process parameters of a DC magnetron sputtering device and their characteristics are analyzed. TiN thin films are deposited on Si wafer (100) substrates by setting the substrate temperatures to ambient temperature, 100, 200, and 300 °C. The residual stress measurement using the XRD method, adhesion characteristic analysis performed using a nanoscratch test to measure the critical load of the nanoindentation device, and leaky surface acoustic wave (LSAW) measurement were conducted using the V(z) technique of the ultrasonic microscope; the correlations between each measurement were analyzed. The residual stress of the TiN thin film was relieved by up to approximately 48% and adhesion properties enhanced by approximately 10% with an increase in the substrate temperature. In addition, the velocity of the LSAW presented a tendency to increase by up to approximately 5%. The residual stress and velocity of the LSAW were found to be inversely proportional, while the critical load and velocity of the LSAW were directly proportional.

Titanium Nitride based multi-functional thin films

The aim of the present work is to demonstrate that the applications of TiN thin films can be expanded well beyond the traditional domains. For example, although TiN is known to exist in several sub-stoichiometric forms their properties have not been exploited fully. Using a patented sputtering process technology, we show that the Ti2N phase is semiconducting, possesses a band gap of the order of 3.5eV and a hardness in the region of 5-7 GPa. Thisimplies that Ti2N thin films can be candidates for light emitting diode applications. In some cases, reflectivity <2% in the visible region was also achieved which is useful for optical shielding applications. The nitrogen stoichiometry and thickness of TiN thin films can be tuned to achieve colours from blue to brown to golden yellow for decorative coating applications. TiN thin films can be a cost-effective replacement for Au since they also display a surface plasmon resonance at the same wavelength. The conductivity of TiN is sufficiently high to replace gold as an electrode material in electronic devices such as diodes. The properties of TiN-Si3N4 and TiN-Polyaniline composite thin films are also reported. The current work, thus, demonstrates the multi-functionality of TiN as an optical, opto-electronic and electronic material.

On the preferred orientation in Ti1–x Al x N and Ti1–x–y Al x Si y N thin films

Abstract The influence of the deposition geometry and the chemical composition on the form and degree of the preferred orientation of crystallites was investigated in TiN, Ti1–x Al x N, and Ti1–x–y Al x Si y N thin films deposited by cathodic arc evaporation. The deposition geometry was varied by changing the angle between the cathodes and the substrates. The chemical composition of the thin films was modified by the choice of the cathodic materials. In TiN thin films, the crystallites were preferentially oriented with the {111} direction perpendicular to the sample surface, independent of the deposition geometry. Besides, a well-pronounced in-plane texture was observed. Co-deposition of Ti, Al, and Si in nitrogen atmosphere stimulated inclination of the texture direction towards the sample surface, which can be described as a change of the texture direction related to the sample surface perpendicular direction, and reduced the amount of the in-plane texture in the coatings (the preferred orientation of crystallites in the plane of the coating).

Oxidation Behavior of Nanostructure Sputtered Titanium Nitride Thin Films

The oxidation behavior of reactive DC magnetron sputtered TiN thin films was investigated under annealing temperature ranging from 400 to 700oC in the ambient atmosphere using X-ray diffraction, energy dispersive X-ray spectroscopy, and field-emission scanning electron microscopy techniques. The oxidation rate and oxidation activation energy of the films were also calculated from parabolic and Arrhenius relations. The as-deposited film had a polycrystalline TiN structure. After annealing at 450oC, the TiO2 rutile structure was found in the XRD spectra and the relative integrated intensity of the oxide phase increased gradually with temperature. The EDS analysis gave confirmation of XRD patterns, showing the expected increase in O content. Grain growth resulting from grain coalescence occurred through the annealing temperatures. The cross-sectional analysis showed that a very thin dense oxide overlayer was present at 400°C and the oxide thickness increased gradually with temperature. Moreover, the films were fully oxidized into a porous structure after 650oC. The results revealed that the films showed an oxidation rate from 400°C and the oxidation activation energy of films was 156.56 kJ/mol.

Atomic layer annealing for modulation of the work function of TiN metal gate for n-type MOS devices

Tailoring the work function of metal gates at a low temperature is critical to the electronic performance of advanced nanoscale MOSFET devices. In this paper, the work function of TiN thin films is effectively altered by the atomic layer annealing (ALA) technique, i.e. the layer-by-layer, in-situ argon plasma treatment incorporated into each atomic layer deposition cycle. The density, stoichiometry, and crystallinity of TiN thin films can be significantly improved by the ALA treatment at a low temperature of only 300℃, which leads to a wide tunability of the work function from 4.52 to 4.03 eV of the TiN metal gate. The sufficiently low work function of 4.03 eV is highly favorable to the low power consumption in n-type MOSFETs. The result indicates that the ALA technique is an advantageous approach to modulating the physical and material properties of metal gates in nanoscale MOS devices by precise energy transfer with atomic-scale accuracy.

Optical and magnetic properties of cobalt doped TiN thin films grown by RF/DC magnetron sputtering

Here we report the study of cobalt doped titanium nitride thin films grown by reactive co-sputtering of cobalt and titanium targets in the presence of argon and nitrogen gases. Thin films were grown with different cobalt concentrations and analyzed by atomic force microscopy, spectrophotometry, X-ray photoelectron spectroscopy, X-ray reflectometry and vibrating sample magnetometry. We have found that the films readily oxidize after exposure to the atmosphere and form a cobalt doped titanium oxynitride. The variable cobalt concentration in the films affects the optical, chemical and magnetic properties. The bandgap of the films generally becomes narrower at higher cobalt concentrations. Cobalt is found to be in a mixture of the high spin + 2 and low spin + 3 oxidation states. At the lower cobalt concentrations, the magnetization is low and it is temperature-independent. Whereas at higher cobalt concentrations, the magnetic response becomes temperature-dependent with a mix of paramagnetism and superparamagnetism at 3–5 K.

Schottky-type GaN-based UV photodetector with atomic-layer-deposited TiN thin film as electrodes.

In this work, a GaN-based UV photodetector with an asymmetric electrode structure was fabricated by atomic layer deposition (ALD) of TiN layers. The thickness of the TiN can be monitored in situ by a quartz crystal microbalance (QCM) and precisely controlled through the modulation of deposition cycles. During the ALD process, periodic variation in the QCM frequency was observed and correlated to the physical adsorption, chemical bonding, and the excessive precursor exhaust, which included tetrakis(dimethylamino)titanium (TDMAT) and N sources. The asymmetric TiN/GaN/TiN photodetector showed excellent photosensing performance, with a UV-visible rejection ratio of 173, a responsivity of 4.25 A/W, a detectivity of 1.1×1013 Jones, and fast response speeds (a rise time of 69 μs and a decay time of 560 μs). Moreover, the device exhibits high stability, with an attenuation of only approximately 0.5% after 360 nm light irradiation for 157 min. This result indicates the potential of TiN as a transparent contact electrode for GaN-based optoelectronic devices.