TiN Films Research Articles

Comparative Study of Titanium Nitride ALD using High Purity Hydrazine vs Ammonia

Emerging devices (Logic and Advanced Memory) require high quality thin (5-20 Å) electrode and barrier films. Difficult thermal budget constraints are now being placed on well-known materials such as TiN and TaN. Deposition temperature limitations have reached 350°C and below while very low resistivity (<100 micro-ohm/cm) must be achieved. Novel Ti precursors are being explored.1 Our approach has focused on hydrazine (N2H4) as an alternative nitrogen source to NH3.Hydrazine is generally difficult to handle from a safety perspective due to its flammability and toxicity. We have developed a novel method to store and generate hydrazine in situ as a high purity gas which is then delivered to ALD process chambers.2 In this study, we examine the effect that hydrazine has on low deposition temperature TiN ALD processes. We experimentally evaluate TiN ALD growth and film characteristics using TiCl4/ N2H4 in comparison to that using TiCl4/NH3.Titanium Nitride films were deposited using the hot wall type tubular furnace and a sequential gas supply system. Deposition temperature was set to predetermined value in the range from 250°C to 400°C. In the case of TiCl4/NH3, GPC was 0.10-0.27 Å/cycle at 250-400°C, where a decrease is noted as the deposition temperature is reduced. With the use of hydrazine, an increase in GPC is observed at each deposition temperature vs NH3. Moreover, the temperature dependence of GPC moved in the opposite direction of TiCl4/NH3. Specifically, GPC of TiCl4/N2H4 ALD was 19% higher at 400°C while an increase of 310% was seen at 250°C versus NH3. In the case of TiCl4/N2H4, the ALD window appears in the range of 250-400°C, where TiCl4 adsorption saturation curves are observed at 250°C and 400°C. Refractive index (R.I.) of TiCl4/N2H4 ALD was about 1.68-1.73 at 250-400°C. These values were approximately equal to R.I. of typical sputtered TiN which was about 1.66. In contrast, R.I. of TiCl4/NH3 ALD was larger than 2.00 in the 250- 300°C range. Because of R.I. of typical titanium oxide is about 2.4-2.5, it is assumed that the TiCl4/NH3 ALD film is contaminated by oxygen. In the ammonia case, background contaminants in the reactor appear to compete with low reactivity NH3 for reaction sites on the ALD surface. In the TiCl4/N2H4 case, higher temperature is not required to form high quality TiN films compared to TiCl4/NH3 ALD.From the above results, the use of high purity hydrazine is beneficial to maintaining high throughput and good film quality under the new constraints for emerging devices. Film composition by XPS and Resistivity measurements consistent with this conclusion will also be presented.

Preparation of Y Doped BaZrO3 Thin Film Electrolyte By Using Laser Chemical Vapor Deposition

It is well known that some cerate based or zirconate based perovskites exhibit proton (H+) conduction at around 600oC [1], and those proton conducting perovskites are expected to be used as electrolyte of proton ceramic fuel cells (PCFCs). Especially, Y-doped BaZrO3 (BZY) has received attention, owing to its higher H+ conductivity than other proton conducting perovskites. However, the densification of BZY basically needs high temperature above 1400oC, leading to a critical problem when the BZY film was prepared on a Ni-based composite electrode; BZY significantly reacts with Ni and forms impurity phase such as BaY2NiO5 during the high temperature sintering [2]. In addition, this impurity phase easily decomposes under H2 atmosphere and causes the critical damage for the cell. D. Han et al. have reported that the BaY2NiO5 impurity phase disappears by heating above 1500oC [4]. However, they also have reported that Y2O3 alternatively appears in the high temperature heating [4]. Thus, a preparation technique that can fabricate thin film at lower temperature, is favorable to avoid the formation of the impurity phase in the case of BZY. Currenlty, the pulse laser deposition (PLD) method has been commonly utilized for the lower temperature deposition of ceramic thin films. However, in the case of PLD, its deposition rate is usually 1 μm/h and its area is several cm2 at best, that is, PLD has a difficulty for the practical use. Besides the PLD method, the laser chemical vapor deposition (LCVD) method, which combines a chemical vapor deposition and laser irradiation, has been proposed as one of the low temperature deposition methods. Recently, Goto et al. have demonstrated the laser chemical vapor deposition of the ceramic thin films at a lower temperature [5,6], and actually, they reported the high-speed deposition of TiN film at several 10 μm/h at 600oC- 800°C [5]. In addition, they demonstrated LCVD on a curved surface and a large surface area [6].Thus, in this work, the preparation of the BZY film was investigated by using LCVD. The deposited BZY film was characterized by XRD, SEM and EDX, and its properties such as structure and chemical composition were analyzed in detail. As a result, it was revealed that the uniform BZY thin film with columnar structure was successfully deposited by the LCVD method. In addition, the thickness of the BZY film was about 16 μm even though its deposition time was only 10 min, suggesting the high speed deposition of BZY film is possible by using the LCVD.[1] H. Iwahara, T. Esaka, H. Uchida, N. Maeda, Solid State Ionics 3/4 (1981) 359-363.[2] L. Bi, E. Fabbri, Z. Sun, E. Traversa, J. Electrochem. Soc. 158 (2011) B797-B803.[3] S. Fang, S. Wang, K. S. Brinkman, Q. Su, H. Wang, F. Chen, J. Power Sources 278 (2015) 614-622.[4] D. Han, Y. Otani, Y. Noda, T. Onishi, M. Majima, T. Uda, RSC Adv. 6 (2016) 19288-19297.[5] Y. S. Gong, R. Tu, T. Goto, J. Alloys Compd. 485 (2009) 451-455.[6] T. Goto, SOKEIZAI 51 (2010) 20-25.

Tailorable stress window of stress-induced martensitic transition in NiTi/W nanostructured multilayer films

NiTi thin films showed superplasticity with recovery strain up to 8%, however their strongly non-linear elasticity caused imprecise position control in MEMS requiring immediate and progressive control. Here, we report NiTi/W nanostructured multilayer films with tailorable stress window via layer spacing modulation. The stress window could be enlarged up to three times larger than that of single-layered NiTi film. Coherent phase boundary between B2 and α-W as well as the large transition strain of NiTi layer led to multilayers collaborative deformation without dislocation slip, making NiTi/W films large strain and strength. On the other hand, grain growth of NiTi layers was confined by W layers, thus layer spacing change could successfully modify the martensitic transition start stress of B2–B19’.

New technique for deposition and thermochemical treatment of small parts with complex geometry applied to machining inserts

Cutting tools, such as machining inserts, which in addition to having a complex geometry need to handle different demands on more than one face during their application, stimulate investigation for new coating techniques. Even though many hard film deposition techniques are well accepted or even established among researchers and industries, these processes still need to meet a limitation that requires the repositioning of the sample for new treatments in order to cover all of its surfaces. This paper proposes a new methodology for coating deposition on complex geometry pieces, through a structure for three-dimensional plasma treatment, using a Rotary Cathodic Cage Plasma Nitriding (RCCPN). TiN films were deposited on cemented carbide inserts applied in machining processes using the RCCPN technique. The plasma parameters were kept constant and deposition time was the only variable input. The deposited films were characterized by SEM, EDS, XRD, and Vickers microhardness. It was observed that the RCCPN technique was useful in producing a uniform TiN layer in all insert surfaces, with a thickness proportional to deposition time.

Characterization of the Hydrogen Migration in a VT1-0 Titanium Alloy by Thermo-EMF and Eddy Current Nondestructive Control Methods

Abstract—The processes of hydrogen migration in a titanium plate and inhomogeneous hydrogen saturation are studied by measuring the thermopower and eddy currents. The processes of inhomogeneous hydrogen saturation of commercial-purity VT1-0 titanium are developed, tested, and investigated using these methods of nondestructive testing. To achieve an inhomogeneous hydrogen concentration in a titanium plate, a TiN film 1–2.6 μm thick is deposited onto it by magnetron sputtering, and the parts of the plate free of the film are hydrogenated. The thermo-emf and eddy currents are measured at various probe coordinates before and after hydrogen saturation of the plate. Eddy current testing demonstrates that, after the plate is hydrogen saturated for 1.5 h, the thermo-emf on the side of hydrogen sorption is significantly lower than on the coated side. After 144 h, a uniform thermo-emf ​​ distribution is obtained, as follows from eddy current measurements. The thermo-emf study is performed upon heating at a constant rate. The thermo-emf of each part of the titanium alloy surface (including the uncoated part) is approximately equal to the value obtained before hydrogenation. The electrical resistivity of the coated titanium plate at room temperature is approximately 0.315 mΩ cm. After hydrogenation, the hydrogen content in the uncoated part decreases slowly. The thermo-emf also decreases gradually. A hydrogen content distribution can be formed via a thermo-emf distribution ​​in the titanium plate. After holding for a sufficiently long time, a uniform thermo-emf distribution forms in the plate.

High temperature wettability and oxidation behavior of TiN, Ti–Al–N and Ti–Si–N PVD film

In aluminium cutting and die casting, tools are exposed to Built UP Edge (BUE) and Built Up Layer (BUL) and erosion due to the frequent contact of the tool surface to the aluminum alloy, to oxidation due to high temperatures. For this reason, the susceptibility to reaction with liquid aluminum and stability of TiN, Ti–Al–N and Ti–Si–N films were investigated using wetting test, high temperature oxidation experiment and complementary differential scanning calorimetry. The results show that the type of chemical bond affects the surface tension, tool steel with metal bonds is most easily wetted, after being wetted and cooled by molten Al at 725 °C, the contact angle is approximately 0°. Because the maximum temperature of the experiment has reached the decomposition temperature of TiN film, therefore, the contact angle of TiN film with ionic bond is 35.3°, slightly larger than tool steel. However, there are complex ionic bond compounds Ti3AlN and covalent bond compounds Si3N4 in Ti–Al–N and Ti–Si–N films, which significantly reduce the wettability of the film with molten aluminum. The contact angles are 78° and 71°, respectively. During the oxidation process, due to Ti–Al–N and Ti–Si–N films contain Al and Si elements, the phase and morphology did not change until 800 °C, this indicates that the effects of different chemical bonds caused by alloying elements on oxidation resistance and wetting resistance have a similar relationship.

Синтез и характеризация наноструктурированных тонких пленок оксида олова, легированных висмутом

The tin dioxide (SnO2) films doped with bismuth by means of magnetron sputtering of semiconductor two-phase target and powder BiO2 as source of Bi were produced. The effect of bismuth dope concentration variation on the microstructure, electrophysical and gas-sensing properties was investigated. It has been found, that films consist of crystalline rods with diameter of 21±2 nm and length of 120±10 nm. Bismuth doping provided decrease in signal timing drift of acetone sensor in analyzed probe. Sensitivity to acetone vapor of the sample derived from targets with 0.01% bismuth oxide concentration increase almost by 10 times (up to 850) in comparison with undoped film at 300°С. Based on the obtained experimental data the mechanism of bismuth dope influence on electrical and gas-sensing properties of produced tin dioxide films was evaluated. Obtained results have shown capability the use of bismuth doped dioxide tin films for development of saturated acetone vapor sensors.

Mechanical and High-Temperature Tribological Properties of Cr3C2-NiCr/TiN Duplex Coating

Preparation of duplex coating is an innovative way to improve components surface in terms of mechanical and tribological properties by the combination of high velocity oxy-fuel (HVOF) and physical vapor deposition (PVD) technologies. The present work focused on the construction, mechanical properties and high temperature tribological behaviors of the duplex coating consisting of a thick HVOF Cr3C2-NiCr interlayer and a thin PVD TiN top layer, as well as compared it with the Cr3C2-NiCr coating and the single TiN film. The results showed that the Cr3C2-NiCr/TiN duplex coating exhibited higher hardness, elastic modulus, H/E and H3/E2 ratios and superior load-bearing capacity than the single TiN film. The introduction of Cr3C2-NiCr intermediate layer did not affect the microstructure of TiN film but significantly improved the adhesion strength between TiN film and substrate, as well as the wear resistance sliding against WC ball at different temperatures. In addition, the friction and wear mechanism of the Cr3C2-NiCr coating, TiN film and Cr3C2-NiCr/TiN duplex coating was revealed by investigating the friction-induced morphological and structural evolutions of the sliding surface at elevated temperature.

ITO induced tunability of surface plasmon resonance of tin thin film

A low-cost tin thin film with different thicknesses was deposited on ITO covered silica substrates via magnetron sputtering. The structure, surface morphology, and optical properties of tin/ITO thin films were investigated via X-ray diffraction (XRD), atomic force microscopy (AFM), UV–VIS-NIR double beam spectrometer, and Raman system, respectively. The results show that by controlling the thickness of the tin thin film with ITO, red shift of the surface plasmon resonance wavelength was achieved and the surface-enhanced Raman scattering (SERS) was enhanced. On the contrary, when no ITO layer was employed in the system, the variation of the tin film thickness did not cause a significant change in the resonance wavelength. Additionally, Finite-Difference Time-Domain (FDTD) was performed for the surface plasmon resonance properties of the samples, and the simulation results were consistent with the experiments.

Investigation of physical and electrical properties of TiN-coated SS316L as bipolar plate of proton exchange membrane fuel cells

ABSTRACT In this research, TiN films were deposited on the SS316L substrate by cathodic arc evaporation technique, to use as bipolar plates in proton exchange membrane fuel cells. The effect of substrate surface roughness and film thickness on the interfacial contact resistance and corrosion properties of the TiN films was investigated. Characterization of deposited films was performed by XRD, XRF, ICR, contact angle, and FESEM equipped with energy-dispersive spectroscopy. Electrochemical and surface properties of deposited films were studied by potentiodynamic scanning, electrochemical impedance spectroscopy, and AFM analysis. It is observed that the surface roughness of the substrate, before deposition, has a significant impact on the final properties of TiN coating, especially when the coating thickness is less than 1.2 µm. All of the coated samples showed better corrosion resistance in comparison to the substrate, and the corrosion current density decreased from 1.65 to 0.16 μA cm–2 when coating thickness increased from 0.6 to 1.5 µm.

Gamma- and x-ray accelerated tin whisker development

We observed accelerated whisker development in thin tin films under non-destructive gamma-ray and x-ray irradiation sources. The effect is mediated by charges induced in glass substrates supporting films, and becomes significant reaching the characteristic range of radiation doses of 20-30 kGy. We were able to change the radiation induced whisker growth rate by electrically disconnecting some parts of our experimental setup, thus demonstrating the electrostatic nature of the whisker development. Subject to additional qualification trials, the observed acceleration factors suggest that ionizing radiation can be used for accelerated whisker propensity testing.

Synthesis of TiN/N-doped TiO2 composite films as visible light active photocatalyst

Titanium nitride/nitrogen-doped titanium oxide (TiN/N-doped TiO2) composite films were synthesized for visible light photodegradation applications. Thin films of TiN were sputter-deposited on precleaned glass substrates in an admixture of argon and nitrogen gases. The grown TiN films were subsequently oxidized in air at 350 °C at 15, 30, and 60 min. Raman spectral analysis revealed the formation of TiO2 with anatase structure at 15 min and transitioned to the rutile structure at longer oxidation times. X-ray photoelectron spectral analysis revealed the formation of N-doped TiO2 from the oxidized Ti. Visible light-induced photodegradation of methylene blue as test analyte showed 30% removal efficiency after exposure to visible light after 2.5 h. The highest degradation efficiency was observed when the anatase phase of TiO2 is the dominant phase in the film. Moreover, N-doping realized the visible light sensitivity of TiO2. This makes the composite film ideal for solar light-driven photodegradation of organic contaminants in wastewater.

Reduced optical losses in refractory plasmonic titanium nitride thin films deposited with molecular beam epitaxy

Refractory plasmonic materials that have optical properties close to those of noble-metals and at the same time are environmentally friendly, commercially viable and CMOS-compatible could lead to novel devices for many thermo-photonic applications. Recently developed TiN thin films overcome some of the limitations of noble-metals, as their optical loss is larger than noble metals and conventional methods to deposit TiN films are not compatible for its integration with other semiconductors. In this work, high-quality epitaxial single-crystalline TiN thin films are deposited with plasma-assisted molecular beam epitaxy (MBE) that exhibit optical losses that are less than that of Au in most part of the visible (300 nm – 580 nm) and near-IR spectral ranges (1000 nm - 2500 nm). In addition, a large figure-of-merit for surface plasmon polariton (SPP) propagation length compared to the previously reported TiN films is achieved with the MBE-deposited films.

Tribological Behavior of Tool Steel Substrate and Solid Films against 304 BA Austenitic Stainless Steel under Dry Sliding

The objective of this work is to study the tribological behavior of the contacting surfaces of SKD11 grade hardened cold work tool steel against grade SUS304BA austenitic stainless steel. DLC, CrN, TiN, and TiCN films were coated on the surface of the tool material to test the tribological performance. Simulation testing with a pin-on-disk was used in this study. The study was done under dry conditions with sliding velocities at 50, 100, and 150 mm/s and contact pressures of 807, 1095, and 1280 MPa. The results show that the main problem is the adhesion of the workpiece material on the tool surface. The severity of the adhesion from the workpiece material is proportional to the sliding velocity and the contact pressure between the contacting surfaces. The coefficient of friction between the contacting surfaces has a positive relationship with the adhesion occurring on the tool surface. The hardness of the film coating is useful for preventing wear of the tool material, especially under high pressure between the contacting surfaces. However, it does not prevent the adhesion of workpiece material of low sliding velocity and low contact pressure conditions. Noncoated SKD11 tool steel has better effectiveness of adhesion performance than CrN, TiN, and TiCN film coatings.

A Tin Film CMK-3 Modified Carbon Paste Electrode as an Environmentally Friendly Sensor to Detect Trace Cadmium

We reported a tin film CMK-3 modified carbon paste electrode (Sn–CMK-3/CPE), a brand new electrode combining the ordered mesoporous carbons (OMCs) and tin film to detect trace cadmium. As one of the OMCs, CMK-3 has the distinct advantage of conducting electrons quickly and good adsorptivity because the pores in it are regularly ordered and controllable with the pore diameters of about 3.8–4.0 nm. Compared to the carbon paste electrode modified by CMK-3 and carbon paste electrode modified by the tin film, the Sn–CMK-3/CPE has higher sensitivity and stability in the process of detecting Cd(II). Under the optimum conditions (mass of CMK-3—4.0 mg; pH 4.70, Sn(II) concentration—6.5 mg/L, deposition potential—1.2 V, deposition time – 300 s), the Sn–CMK-3/CPE indicated a wide linear concentration range of 6–100 μg/L with the detection limit of 0.8 μg/L for Cd(II). This novel sensor was applied to the detection of Cd(II) in river samples with good recoveries.

Synthesis of TiN and TiO2 thin films by cathodic cage plasma deposition: a brief review

The cathodic cage plasma deposition (CCPD) is an advanced technique recently developed from an active screen plasma nitriding system, which has been used for thin film deposition such as titanium nitride and titanium dioxide (TiO2). These coatings can improve the physical, mechanical, and optical properties of numerous materials, and such coatings can be developed by several techniques. Unfortunately, the conventional deposition techniques exhibit certain drawbacks, including high cost, the complexity of the operation, very low pressure, and high processing temperature; as a result, CCPD is an advantageous technique. In this review, brief information on the deposition of titanium nitride and oxide coatings on steel alloys, titanium, glass, and silicon substrates, and the effect of control parameters on deposition efficiency is provided. The effectiveness of this system for the synthesis of thin films on various substrates, including insulators and conductors, is also summarized. The recent developments and applications of CCPD for titanium-based coatings are described in detail.

Biocompatibility of Ti-Mn-N films with different manganese contents

Ti-Mn-N films were deposited on CoCrMo alloys and Si substrate by reactive magnetron sputtering. The effects of Mn content on the structure, surface composition and surface energy of Ti-Mn-N film were investigated by XRD, SEM, XPS, and contact angle measurements. Primary mouse osteoblasts were cultured on the Ti-Mn-N films for 1 and 3 d to evaluate cell adhesion and cell viability. RAW264.7 macrophages were cultured on the Ti-Mn–N films for 24 h to evaluate the cell activation and inflammatory cytokine release. The results showed that after culturing for 3 days, there were a greater number of osteoblasts on the 2.2%Mn-TiN and 4.4%Mn-TiN films as compared to the other films. When the Mn content was higher than 4.4 at.%, the osteoblasts viability on Ti-Mn-N films was reduced. In addition, the results of the released inflammatory factors showed that Ti-Mn-N films induced a lower inflammatory response than that induced by CoCrMo alloy, while demonstrating the same excellent biocompatibility as that of TiN film. Hence, Ti-Mn–N films with 2.2 at.% and 4.4 at.% Mn have potential application on the surface modification of dental implant.

Superconductivity in a disordered metal with Coulomb interactions

We study the electronic densities of states (DOS) of strongly disordered superconducting thin films of TiN. We find, using Scanning Tunneling Microscopy (STM) that the DOS decreases towards the Fermi level in the normal phase obtained by applying magnetic fields. The DOS shows spatial fluctuations whose length scale is related to the energy dependent DOS and is similar in normal and superconducting phases. This suggests that Coulomb interactions lead to a spatially varying DOS in the normal phase of a disordered superconductor.

A note on the effect of surface energy on the growth of a tin whisker

ABSTRACT In this communication, we report theoretical analysis of the contribution of surface energy to the energy dissipation during the growth of a tin whisker in a tin film. The mass transport of tin for the growth of the tin whisker is grain-boundary diffusion. The surface energy hinders the growth of the tin whisker. There is a threshold of the strain energy stored in the tin film, below which no whiskers of corresponding radius can grow. The strain energy stored in a tin film prior to the formation of a whisker determines the growth time of the whisker if there are no other mechanisms for the dissipation and generation of strain energy.

증착 후 전자-빔 조사 에너지에 따른 질화티타늄 박막의 특성

In this study, the effect of electron beam irradiation on surface properties, such as hardness, adhesion, and surface roughness, of TiN films was investigated. The films were deposited on an SKD-61 substrate through cathodic arc ion plating. After deposition, the films were bombarded with an intense electron beam under incident energies of 500, 1000, and 1500 eV for 10 min. From the results, the surface hardness increased up to 3357 HVIT at 1500 eV, and the critical load increased proportionally with irradiation energy from 15.8 to 23.4 N. In addition, the surface root-mean-square roughness of the films was significantly influenced by electron irradiation. Films subjected to electron irradiation at 1500 eV exhibited the lowest roughness of 397 nm.