TiN Thin Films Research Articles

Physical-Vapor-Deposition-Coated Natural Rocks as Sustainable Cutting Material: First Insights into the Effect of Substrate Integrity on Properties of TiN Thin Film

The most important cutting materials for machining are carbides. Their production requires both tungsten and cobalt; however, these materials are becoming increasingly difficult to obtain and are sometimes mined under ethically questionable conditions. As a result, increasing efforts are being made to expand the range of cutting materials. The basic suitability of natural rocks for cutting tools in less demanding processes has already been demonstrated. PVD coating of the natural rocks could improve their performance. The adhesion mechanisms in TiN-coated natural rock samples are discussed below. The TiN thin film is characterized in depth.

From weak to strong-coupling superconductivity tuned by substrate in TiN films

Abstract The interplay between substrates and superconducting thin films has attracted increasing attention. Here, we report an in-depth investigation on superconducting properties of the epitaxial TiN thin films grown on three different substrates by dc reactive magnetron sputtering. The TiN films grown on (0001) sapphire exhibit (111) crystal orientation, while that grown on (100) Si and MgO substrates exhibit (100) orientation. Moreover, the samples grown on Si reveal a relatively lower level of disorder, accompanied by the higher critical transition temperature Tc and smaller magnitude of upper critical field slope near Tc. Remarkably, we uncovered a rather high value of superconducting gap (with Δ0/kBTc = 3.05) in TiN film on Si indicating a very strong coupling superconductivity, in sharp contrast to the case using sapphires and MgO as the substrate which reveals a weak-coupling feature. The comprehensive analysis considering the scenarios of the three substrate shows that the grain size of the thin films may be an important factor influencing the superconductivity.

Novel synthesis of 1-D silicon nanowires grown on pyramidal black silicon substrates and intense visible emission

This work shows a new way to grow 1-D Silicon Nanowires (SiNWs) over pyramidal black silicon used as substrates. These nanostructures are grown by the plasma-assisted vapor–liquid-solid (VLS) as a bottom-up process, using tin thin films as a catalytic metal and dichlorosilane gas as a silicon precursor. SiNWs were obtained with diameters from 300-600 nm and 4–6 µm lengths on the black silicon surface. Due to the pyramid-shaped and porous nature of the black silicon surface, SiNWs form a complex mesh nanostructure. This network has a large surface area and exhibits intense and effective photoluminescence with a peak in the green spectrum, which is attributed to the quantum confinement effect that occurred in small nc-Si embedded inside SiNWs. These structural configurations hold significant promise for applications in optical biosensors, solar cells, and other prospective fields.

Improved SERS activity of TiN microstructures by surface modification with Au

Over the years, numerous outstanding research groups around the world have been working tirelessly on metallic SERS substrates. Although these efforts have led to the development of various sensors and pushed the field forward, today this line of research seems saturated and exhausted. In this work, we address this issue by exploring an emerging topic in recent literature: the fabrication of high-performance TiN SERS-active structures. TiN thin film was sputtered onto pyramidal Si microstructures. Spectroscopic ellipsometry measurements confirmed the plasmonic properties of the TiN material above its plasma wavelength of 515 nm. The Si-TiN surface was subsequently modified with an Au layer, which was then transformed into Au nanoparticles (Au NPs) during the Rapid Thermal Annealing process. The Si-TiN-AuNPs samples exhibited the highest extinction intensity, as well as the best SERS signal intensity for the model Raman reporter molecule. Further analysis of the SERS data showed that the presence of the Au thin film only moderately increased SERS activity, while Au NPs enhanced the SERS signal by one order of magnitude. Final Si-TiN-AuNPs platforms were successfully employed for the detection of vitamin B12, demonstrating a low limit of detection (8.57•10–8 M) along with excellent point-to-point repeatability.Graphical abstract

Effect of bottom critical dimension (CD) size on TiN residual

Abstract The relationship between bottom critical dimension (CD) size and TiN residual in semiconductor manufacturing was elucidated. As an excellent electrode material, TiN needs to be cut from the continuous TiN film during the capacitor preparation process to achieve parallel connection of capacitors and increase capacitance. However, TiN film may only partially be removed under different process conditions. To illustrate the reason for TiN residual and its relationship with bottom CD size, the TiN and oxide thin films were deposited by atomic layer deposition (ALD) and plasma enhanced chemical vapor deposition (PECVD), respectively. The results show that the amount of TiN residual and bottom CD size was strongly coupled when the bottom CD size larger than 140 nm TiN can be fully removed. However, if the trench bottom CD size is smaller than 85 nm, there are different degrees (residual TiN thickness within the various of 1.8-11 nm) of TiN remain. Therefore, the results of this paper are of much importance as a reference for process design.

Thickness uniformity, electrical properties, and stress of sputtered TiN thin films

Thickness uniformity, electrical properties, and stress of sputtered TiN thin films

Optical behaviour of magnetron sputtered nano-hilled TiN coatings

Cylindrical magnetron sputtered TiN thin films have been grown on glass (G) and quartz (Q) substrates to examine optical properties under two flow conditions: increasing nitrogen flow rate (1 → 35 sccm): (I) and decreasing nitrogen flow rate (35 → 1 sccm): (D). The optical properties of the film are characterized using UV–Vis-NiR spectroscopy, spectroscopic ellipsometry, and photoluminescence studies. Films deposited under both parameters exhibited excellent UV-restriction properties. Nano-hilled topography of the film contributed to multiple reflections and scattering of incident light on both quartz and glass specimens. Clustering of nano-particles in G(D) specimen increases the light interaction and absorption within the film leading to higher absorbance and lower transmittance properties compared to G(I). TiN-Quartz specimen displayed better UV absorbing properties compared to TiN-Glass as confirmed through ellipsometry studies. lack of phonon-related transitions in Tauc's plot indicated the involvement of direct allowed transitions.

Duplex surface engineering of cold spray Ti coatings and physical vapor-deposited TiN and AlTiN thin films

The feasibility of a duplex coating based on cold spray technology and magnetron sputtering was evaluated for repair applications requiring a ‘thin-on-thick’ layered structure. Commercially pure angular-shaped Ti grade 4 particles are fed to a cold spray gun and accelerated toward a Ti alloy substrate to deposit thick coatings (∼4.5 mm). TiN and AlTiN thin films are deposited on polished cold spray coatings using a four-source closed-field unbalanced magnetron sputtering (CFUBMS) system. Microstructure was characterized using focused ion beam (FIB) lift-out, scanning electron microscopy (SEM), and electron channeling contrast imaging (ECCI). The nanoindentation technique was used to evaluate the mechanical properties of coatings. The H/E ratios and H3/E2 ratios for TiN films were found to be 0.098 and 0.26 GPa, respectively, while those for AlTiN films were measured at 0.066 and 0.052 GPa, respectively, suggesting higher capacity of TiN films to withstand both elastic and plastic deformation. Using scratch testing, the adhesion of TiN and AlTiN thin films to cold spray Ti was investigated, with TiN-Ti duplex coatings exhibiting better performance compared to AlTiN-Ti coatings. Tribological testing was performed on duplex coatings using a reciprocating tribometer equipped with an alumina ball counterface. The wear rate for AlTiN-Ti coatings after 2000 sliding cycles was found to be (1.0 × 10−3 ± 0.1 × 10−3 mm3/Nm), three orders of magnitudes higher than that for TiN-Ti (8 × 10−6 ± 2 × 10−6 mm3/Nm. SEM was used to reveal worn surface morphologies and cross-sectional analysis of the wear track. Subsurface microstructural changes due to wear were examined using focused ion beam cross-sectioning, revealing bending cracks and tribofilm formation.

Emergence of quantum Griffiths singularity in disordered TiN thin films

The association of quantum Griffiths singularity (QGS) to the magnetic-field-induced superconductor-metal transition predicts the unconventional diverging behaviour of dynamical critical exponent in low disorder crystalline two-dimensional superconductors. But whether this state exists in the superconducting systems exhibiting superconductor-insulator transition remains elusive. Here, we report the emergence of quantum Griffiths singularity in ultrathin disordered TiN thin films with more than two orders of magnitude variation in their normal state resistance. For both superconductor-metal transition and superconductor-insulator transition types, a diverging critical exponent is observed while approaching the quantum phase transition. Further, the magnetoresistance isotherms obey a direct activated scaling governed by an infinite-randomness fixed critical point. Finally, this work establishes the robustness of the QGS phenomenon towards a wide range of temperature and also towards a wide range of disorder strength as correlated with the normal state resistance.

Synthesis of high conformalty Ti-Six-N films using (CH3)3CCl and SiH4; density functional theory simulation and film characterization

The step coverage of the atomic layer deposition (ALD) of Ti-N thin films was improved by the addition of (CH3)3CCl, and Si atoms were added during the Ti-N deposition to form a Ti-Six-N thin film. By ALD, four to eight cycles of the gas (CH3)3CCl/TiCl4/NH3 formed the Ti-N layer and, subsequently, one to two cycles of the gas SiH4/NH3 added Si atoms to formed the Ti-Six-N layer. The ALD process was repeated to form a thin film Ti-Six-N 150 Å (bilayer of (Ti-N) 80 Å + (Six-N) 70 Å) while adjusting the amounts of (CH3)3CCl and SiH4. The crystallinity of Ti-N was studied by X-ray diffraction (XRD), and its composition was studied using X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The composition of the Ti-Six-N film was studied using electron energy loss spectroscopy and selected area electron diffraction, and its roughness was confirmed using atomic force microscopy. Transmission electron microscope was used to measures the thickness and composition of the Ti-Six-N film through location in a test pattern with an aspect ratio of 50:1. Step coverage improved to 99.9 % compared to conventional ALD Ti-N when using (CH3)3CCl. Additionally, (CH3)3CCl was more effective at lower temperatures (460 °C compared to 530 °C), and the effect of the (CH3)3CCl flow rate was saturated above 300 sccm.As the amount of (CH3)3CCl increased, the growth per cycle decreased from 0.29 Å/cycle to 0.15 Å/cycle. The addition of Si to the Ti-N film facilitated leakage gain by increasing the difference in the work function between the electrode and the capacitor, material but may have the side effect of pillar bending due to a decrease in crystallinity and hardness. We verified that the XRD (200)/(111) peak ratio decreased as the Si content increased. As a result, the optimal conditions for electrode Ti-Six-N were confirmed as follows: 300 sccm (CH3)3CCl Ti-N, SiH4 10 sccm Six-N combination.Furthermore, the Ti-Six-N layer can serve as the bottom electrode of a capacitor reduce the manufacturing process steps, and be a candidate for a solution for the electrode of the capacitor of a 5 nm node memory device.

The Effect of Deposition Temperature on TiN Thin Films for the Electrode Layer of 3D Capacitors Prepared by Atomic Layer Deposition

The TiN thin film is considered a promising electrode layer for 3D capacitors. In this study, TiN thin films were prepared on Si substrates using atomic layer deposition (ALD) at various temperatures from 375 °C to 475 °C. The crystallization behavior, microstructure, and conductance properties of those TiN thin films were investigated. The resistivity of TiN thin films deposited on Si wafers can reach as low as 128 μΩ·cm. TiN thin films showed lower resistivity and worse uniformity with the deposition temperature increasing. In addition, the aging of TiN thin films may weaken the device performance. Optimized deposition parameters were found and full-coverage deposition of thin films on the wall of deep holes with an aspect ratio of approximately 14 has been successfully achieved. The results would be a good reference for the development of 3D capacitors and other microelectronics components.

Nanomechanical inhomogeneities in CVA-deposited titanium nitride thin films: Nanoindentation and finite element method investigations

Refractory metals that can withstand at high temperatures and harsh conditions are of utmost importance for solar-thermal and energy storage applications. Thin films of TiN have been deposited using cathodic vacuum arc deposition at relatively low temperatures ∼300 °C using the substrate bias ∼ −60 V. The nanomechanical properties of these films were investigated using nanoindentation and the spatial fluctuations were observed. The nanoindentation results were simulated using finite element method through Johnson-Cook model. A parametric study was conducted, and 16 different models were simulated to predict the hardening modulus, hardening exponent, and yield stress of the deposited film. The predicted values of elastic modulus, yield stress, hardening modulus and hardening exponent as 246 GPa, 2500 MPa, 25000 MPa and 0.1 respectively are found to satisfactorily explain the experimental load-indentation curves. We have found the local nitridation plays an important role on nanomechanical properties of TiN thin films and confirms that the nitrogen deficient regions are ductile with low yield stress and hardening modulus. This study further opens the opportunities of modelling the nanoscale system using FEM analysis.

Influence of Laser Energy on the Structural and Optical Properties of Sn Nanoparticles produced with Laser-Induced Plasma

This study aimed to investigate the structure and optical properties of Sn nanostructures. Thin tin (Sn) films were deposited on glass substrates using the pulsed laser deposition method. Nd:YAG laser with fundamental wavelengths of 532 nm and 1064 nm was used to create Sn nanostructures with varying energies of 400 mJ to 700 mJ and the same frequency of 6 Hz. The tin powder was compressed into a disc with a one-centimetre diameter to serve as a sample. The X-ray diffraction (XRD) pattern showed a crystalline structure with several Sn nanostructures peaks at various energies (400–700 mJ). The results revealed a crystalline size of 65.90 nm and 86.55 nm at 700 mJ, while the size was 40.19 nm and 17.19 at 400 mJ for the given wavelengths (532nm and 1064 nm), respectively. The appearance of Sn nanostructures and the aggregation of, particularly in the form of cauliflower, were revealed in Field emission scanning electron microscopy (FE-SEM) images. The results of the dispersive energy X-ray spectroscopy (EDS) analysis showed that various amounts of tin, carbon, and oxygen were present. Additionally, the optical characteristics were investigated of each film using absorbance spectra, which covered a range of wavelengths from 190 to 1100 nm. As the laser power increased, the band gap energy values in the optical properties decreased, falling into the ranges of 3.06 to 1.65 eV and 3.22 to 1.82 eV at 1064nm and 532nm, respectively.

Influence of Flow Rates and Flow Times of Plasma-Enhanced Atomic Layer Deposition Purge Gas on TiN Thin Film Properties

Influence of Flow Rates and Flow Times of Plasma-Enhanced Atomic Layer Deposition Purge Gas on TiN Thin Film Properties

Cyclic stability in NiTi and NiTiCu thin films: Role of precipitates in low- and high-cycle regimes

This study examines the influence of precipitates on the cyclic behavior of submicron-thick NiTi and NiTiCu thin films by conducting tensile and fatigue experiments. X-ray diffraction confirmed that both materials contain austenitic phases at room temperature. NiTi has exhibited superior cyclic stability in the low-cycle regime when compared to NiTiCu, while the cyclic stability of NiTiCu surpasses that of NiTi in the high-cycle fatigue regime. The enhanced cyclic stability of NiTi films in the low-cycle regime is attributed to the homogeneous distribution of semi-coherent Ni4Ti3 precipitates within the grain interior. In contrast, the reduced cyclic stability of NiTiCu films can be directly correlated to the presence of incoherent (Ni,Cu)2Ti precipitates at grain boundaries. Conversely, NiTiCu exhibited enhanced cyclic stability under rising stress ratio, attributable to a notable reduction in hysteresis area.

Hardness and Microstructure of TiN Coating on Aluminum Alloy with DC Sputtering

Titanium Nitride coating has attracted much interest in increasing the hardness of aluminum alloys. This study aims to investigate the effect of Ar: N gas mixture and time on increasing the hardness of aluminum alloys using DC sputtering. Preparation of TiN thin films on aluminum alloy substrates using flowing gas mixture parameters and time. First, the layer of TiN was deposited on the sample with a gas mixture of 90Ar:10N; 80Ar:20N; 70Ar:30N; and 60Ar:40N (%) for 60 minutes. Then the optimum gas mixture that produces the highest surface hardness is used in the second process with time variations of 30, 60, 90, and 120 minutes. The results showed that the highest hardness was achieved in a gas mixture of 70Ar:30N and 60 minutes. The TiN phase formed on the aluminum surface was identified by XRD, while the surface morphology was observed by SEM. Compared with untreated samples, the hardness of treated samples increased significantly.

Optimizing Ti/TiN Multilayers for UV, Optical and Near-IR Microwave Kinetic Inductance Detectors

Microwave Kinetic Inductance Detectors (MKIDs) combine significant advantages for photon detection like single photon counting, single pixel energy resolution, vanishing dark counts and µs time resolution with a simple design and the feasibility to scale up into the megapixel range. But high quality MKID fabrication remains challenging as established superconductors tend to either have intrinsic disadvantages, are challenging to deposit or require very low operating temperatures. As alternating stacks of thin Ti and TiN films have shown very impressive results for far-IR and sub-mm MKIDs, they promise significant improvements for UV, visible to near-IR MKIDs as well, especially as they are comparably easy to fabricate and control. In this paper, we present our ongoing project to adapt proximity coupled superconducting films for photon counting MKIDs. Some of the main advantages of Ti/TiN multilayers are their good control of critical temperature (Tc) and their great homogeneity of Tc even over large wafers, promising improved pixel yield especially for large arrays. We demonstrate the effect different temperatures during fabrication have on the detector performance and discuss excess phase noise observed caused by surface oxidization of exposed Si. Our first prototypes achieved photon energy resolving powers of up to 3.1 but turned out to be much too insensitive. As the work presented is still in progress, we also discuss further improvements planned for the near future.

Deposition and nanoindentation study of a novel TiNi/Ag bi-layer shape memory film

Compositions, surface morphologies and mechanical properties of a novel designed TiNi/Ag bi-layer film grown by DC magnetron sputtering at various processes have been investigated. Ar pressure and sputtering power had significant effects on quality and composition of TiNi/Ag bi-layer films. The TiNi/Ag bi-layer film processed by sputtering under high Ar pressure (0.36 Pa) was porous, while better density films can only be obtained at low pressure (0.12 Pa). The composition of TiNi/Ag bi-layer films can be adjusted by sputtering power. The load-displacement curves show the multiple “pop-ins”along nanoindentation loading, as indentation depth does not exceed the pure Ag film thickness (∼340 nm). At the maximum loading of 140 mN, martensitic transformation induced by nanoindentation in TiNi/Ag bi-layer films was not found, and depth recovery ratio was 39%. Moreover, based on the load displacement curve analysis, the hardness and elastic modulus values of TiNi/Ag bi-layer films were 4 ± 0.2 Gpa and 79 ± 2 Gpa, respectively. Comparing with martensitic phase of single-layer TiNi thin films at room temperature, the coexistence of parent phase and martensitic phase of TiNi/Ag bi-layer films were mainly due to strong confinement effect of Ag layer deposition on TiNi thin film. The residual stress calculated by using conventional sin2ψ method was around −0.458 GPa. The present study provided an important theoretical basis for the preparation of TiNi/Ag bi-layer film with higher quality and performance.

Optimization of TiN/TiOxNy Laminated Electrode Films for High-Performance Gene Sequencing Chip

With continuous advancement of the fourth generation nanopore gene sequencing technology, the requirements for performance of the electrode films in gene sequencing chips are increasing. This study utilized the high vacuum reactive magnetron sputtering method to examine the impact of working pressure on the electrical, electrochemical, crystal structure, chemical composition, and surface morphology of TiOxNy thin films in detail. The findings revealed that the TiN thin film deposited at 0.4 Pa exhibited the lowest resistivity of 391.9 μΩ·cm. Additionally, the TiOxNy thin film deposited at 1.6 Pa demonstrated the highest volumetric specific capacitance of 35.37 mF·cm−2·μm−1 at 5 mV·s−1. Utilizing the optimal parameters, TiOxNy laminated electrode thin films were in situ grown. Through measurements and analysis, it was found that the TiOxNy electrode thin film effectively achieves a 29.35% improvement in specific capacitance compared to the single layer TiOxNy electrode thin film. The integration of a TiN current collector with low resistivity effectively reduced the internal resistance of the electrode system and decreased the response time to 0.038 s. The features of low impedance and high specific capacitance of TiOxNy laminated thin films offer promising prospects for the preparation of gene sequencing chip with high throughput.

Some aspects of the resistive-to-normal state transition caused by direct and microwave currents in superconducting thin films with phase slip lines

Based on analysis of current-voltage characteristics and imaging of the resistive state of thin-film tin strips using low-temperature laser scanning microscopy (LTLSM), the process of destruction of superconductivity by current and microwave irradiation with the formation and spatial rearrangement of the order parameter phase slip lines, and their transformation into discrete localized normal domains are shown. The prospects of LTLSM are considered from the point of view of the study of the high-frequency properties of superconducting structures and spatial characteristics in the pre-critical state for instrumental applications.