Zirconium Nitride Thin Films Research Articles

Influence of corrosion on the morphology and structure of ZrOxNy[sbnd]ZrN coatings deposited on stainless steel

Morphological and structural changes of zirconium nitride and oxynitride thin films (ZrOxNy/ZrN) deposited via DC magnetron sputtering on stainless steel substrates (AISI 316L, 304LS, and 2205) in a reactive N2 and N2/O2 atmosphere mixed with argon were studied. The crystallographic structures of the films were established through X-ray diffraction (XRD). The morphology was evaluated via scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the corrosion resistance was evaluated using electrochemical techniques based on linear polarization (PL). The XRD analysis showed that the films were composed of cubic ZrOxNy and monoclinic ZrO2. The electrochemical test showed that there was corrosion because of pitting phenomena and delamination in the coating deposited on AISI 2205 and AISI 304LS substrates. For AISI 316L, the damage generated by the corrosive solution was less. On the various substrates, an increase in the films' roughness was observed after the corrosion test.

Nanomechanical properties of TiN/ZrN multilayers prepared by pulsed laser deposition

The ability to control matter at the range of micron as well nanometer is crucial for material science and engineering. In the domain of material science, the transition metal (TM) nitrides find a unique place owing to their excellent properties such as wear resistance, high hardness and etc. These excellent properties recommended TM nitrides to be used as hard and protective coatings. Further improvements of the mechanical properties were reported by using either ternary compounds such as TiSiC, TiSiN, TiAlN, multilayer or bilayers structures. Here we report the preparation of of multilayer with no of layers of 2,4,10 of titanium nitride (TiN)/zirconium nitride (ZrN) thin films on single crystal Si(100) substrate by using pulsed laser deposition with Nd-YAG laser operating at a wavelength of 1064 nm, pulsed duration 6 ns and repetition rate 10 Hz. The multilayers are grown by ablating from the targets of Zr and Ti in reactive DC nitrogen plasma at a substrate temperature of 673 K at a nitrogen partial pressure of 2x10-3mbar. We investigated the mechanical properties and roughness analysis by Nanoindentation and Atomic force microscopy. Grazing incidence X ray diffraction was used to identify the phase presence in multilayers of TiN/ZrN and cross sectional scanning electron microscopy was used to examine the microstructures and thickness of bilayers. The nanoindentation results showed that peak in hardness was observed in (TiN/ZrN) 2 about 18 Gpa and young’s modulus 250 Gpa

Structures, morphologies, and chemical states of sputter-deposited CrZrN thin films with various Zr contents

Chromium zirconium nitride (CrZrN) thin films were prepared on Si wafers and glasses at various Zr contents by reactive DC magnetron co-sputtering of Cr and Zr metals in Ar and N2 mixture without voltage biasing and external heating. Influences of the Zr contents on crystal structure, cross-section morphology, surface morphology, and chemical composition and chemical state were investigated by X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. The results showed that N content in the films was increased when Zr content increased. Film microstructure changed from coarse columnar to finer-grain morphology and film surface became smooth caused by grain refinement. Zr–metal and Zr–N bonding fractions were increased with the increasing Zr content, whereas Cr–N was decreased due to being substituted by Zr of Cr atoms in the fcc B1 type crystal structure of (Cr, Zr)N. In addition to an increase in lattice parameter, the substitution of Zr could lead to an increase in interatomic distances which affected bonding length between metals and nitrogen atoms. According to the charge potential model, the increase in bonding distances between atoms resulted in negative shifts in binding energy of electrons of all elements that led to observation of lowering in the separation between photoelectron lines of Cr, Zr, and N elements. The lower separation with the increase of Zr content suggested that bonding between metals and nitrogen became stronger due to the dominance of the covalent character as evidenced by the enhanced hardness of the CrZrN materials.

Carbon ions irradiation induced modifications in structural and electrical resistivity characteristics of ZrN thin films

Zirconium nitride (ZrN) thin films are irradiated with 800keV energetic carbon (C) ions in a 5UDH-Pelletron accelerator and the ions irradiation induced effects are investigated. The films are irradiated at various C ions fluences, ranging from 1013 to 1015ions/cm2. The scanning electron microscopy study of the films indicates the development of zirconium (Zr) nanoparticles at ions irradiated region. X-ray diffraction (XRD) patterns of C ions irradiated films also show the formation of (100) and (002) oriented nanocrystalline metallic Zr phases. The irradiated films spectra depict a shift in ZrN peaks towards higher 2θ values, exhibiting that C ions bombardment induces compressive stress in the irradiated films. The appearance of C related peaks in Fourier transform infrared (FTIR) spectra confirms the incorporation of C atoms into ZrN film. Compressive stress has been calculated from the IR peak shift which indicates that higher ion dose (≥5×1014ions/cm2) produce lower compressive stress relative to the lower ions fluences. Effect of ion dose on the film resistivity is also reported.

Low temperature plasma enhanced atomic layer deposition of conducting zirconium nitride films using tetrakis (dimethylamido) zirconium and forming gas (5% H2 + 95% N2) plasma

Zirconium nitride (ZrN) has the lowest bulk electrical resistivity and high thermal stability among group IV and V transition metal nitrides, which makes it a promising material for ULSI applications such as a diffusion barrier for Cu interconnects, contact metal in III-V semiconductor devices, and in high density memory structures. Plasma enhanced atomic layer deposition (PEALD) of conducting ZrN thin films using Zr[N(CH3)2]4 and forming gas (5% H2 + 95% N2) plasma is reported in this article. The growth per cycle (GPC) for every deposition was determined from analysis of dynamic in-situ spectroscopic ellipsometry (d-iSE) measurements. An experimental design is proposed for faster determination of ALD growth saturation curves. At substrate temperature of 150 °C, a GPC of 0.10 nm/cycle was observed for self-limiting ZrN PEALD growth. The electrical resistivity of ZrN films deposited on SiO2 substrate was found to be 559.5 ± 18.5 μΩ cm with negligible change in resistivity even after ∼1000 h exposure to air. The metallic behavior of our ZrN films was evident from the free electron dispersion component in dielectric response, the broad band of photoelectron emission across Fermi level and the positive temperature coefficient for resistivity of 0.0088/ °C.

Probing initial-stages of ALD growth with dynamic in situ spectroscopic ellipsometry

The initial stages of ALD surface reactions are probed using dynamic in situ spectroscopic ellipsometry (d-iSE) technique during plasma-enhanced ALD of zirconium nitride (ZrN) thin films in spectral range of 0.73–6.4eV. The measured change in the ellipsometry parameter Δ, with every precursor (TDMAZr) and reactant (forming gas plasma) exposure is interpreted as the combined effect of film growth and change in surface chemistry during ALD. We present application of Bruggeman's effective-medium approximation (B-EMA) in the analysis of d-iSE data to determine fractional surface coverage (θ) of ALD grown film at the end of every deposition cycle. During the deposition of first few ZrN monolayers, d-iSE datasets are analyzed on the basis of surface diffusion enhanced ALD growth, where the surface adsorbed precursor molecules can diffuse over substrate surface to occupy energetically favorable surface sites. The determined surface coverage of ZrN films highlights the effects of substrate enhanced ALD growth.

Structural and electrical resistivity characteristics of vacuum arc ion deposited zirconium nitride thin films

Zirconium nitride (ZrN) thin films were grown on glass and aluminum substrates using a dual cathodic arc ion deposition technique. The effects of various negative bias voltages and flow ratios of N2/Ar on the stoichiometric ratio of nitrogen to zirconium (N/Zr), deposition rate, structure, surface morphology and electrical resistivity of the ZrN layer were investigated. Rutherford backscattering spectroscopy measurements indicated a drop in the deposition rate and a slight increase in stoichiometric ratio (N/Zr) with the increase of bias voltage up to −400V, although the latter still remained slightly less than unity (~0.92). Deposition rate of the film showed an increase with the argon addition. X-ray diffraction patterns depicted mostly polycrystalline nature of the films, with preferential orientation of (200) planes in the −100V to −300V bias voltage range. For 70–50% nitrogen and at a bias voltage of −400V, the (111) orientation of ZrN film predominated. The films were smoother at a lower bias of −100V, while the roughness increased slightly at a higher bias voltage possibly due to (increased) preferential re-sputtering of zirconium-rich clusters/islands. Changes in the resistivity of the films were correlated with stoichiometry, crystallographic orientation and crystalline quality.

Microstructure, residual stress and hardness study of nanocrystalline titanium–zirconium nitride thin films

The pulsed cathodic arc deposition technique was used to synthesize titanium–zirconium nitride (TiZrN) thin films at different substrate temperatures. A microstructural analysis extracted from the X-ray powder diffraction pattern was performed to identify the dependence of crystallite size and microstrain on TS. The residual stress state was also determined with the X-ray powder diffraction pattern assuming that the material behaved isotropically based on Young׳s modulus and the Poisson coefficient. The morphological analysis used atomic force microscopy to determine the grain size evolution with substrate temperature during deposition. The nanohardness values were obtained using nanoindentation measurements. Finally, the synthesis–property relationships were obtained with the microstructural information.

Effect of Substrate Bias Voltage on the Physical Properties of Zirconium Nitride (ZrN) Films Deposited by Mid Frequency Reactive Magnetron Sputtering

Present work involves the preparation of Zirconium Nitride thin films on stainless steel (SS) (304L grade) substrate by reactive cylindrical magnetron sputtering method. The X-ray diffraction (XRD) profile of the ZrN thin films prepared with different bias voltage conforms face centered cubic structure with preferred orientation along the (111) plane at lower bias voltage (100 V) and at higher bias voltage (300 V) the preferred orientation shifted to (220) plane. The influences of bias voltage on the thickness and microhardness ZrN thin films have been studied. ZrN thin film sputtered with 300 V bias voltage shows the maximum reflectance of 90% at a wavelength of 1000 nm. The coated substrates have been found to exhibit improved corrosion resistance compared to the SS plate. The root mean square surface roughness and surface morphology were investigated from 3D atomic force microscope (AFM) images and scanning electron microscope (SEM), which indicate smooth and uniform surface pattern without any pin holes.

Study of Deposition Temperature Effect on Defect Density in ZrN Thin Films by Positron Annihilation

Zirconium nitride (ZrN) thin films deposited on silicon substrates by PVD reactive sputtering at different substrate temperatures were studied by positron annihilation spectroscopy. The performance of such hard coatings is controlled by their microstructure in which open volume defects play a large role. The results show lower concentration of vacancies as the deposition temperature is increased, very short positron diffusion lengths in all samples indicate the existence of high density of grain boundaries which means small grain sizes. The optimum deposition temperature was observed to be between 300°C and 400°C. The study shows the importance of the positron spectroscopy as a motoring tool for the development of ZrN films.

Effect of Thickness on Microstructure, Electrical and Optical Properties of Zirconium Nitride Thin Film Prepared by DC Reactive Magnetron Sputtering at Room Temperature

Zirconium Nitride (ZrN) thin films were prepared by dc reactive magnetron sputtering without an external substrate heating on silicon (100) wafer and glass slide. The as-deposited films obtained from different conditions and various films thickness was investigated for physical, optical and electrical properties. First, the microstructure and film morphology were examined by X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM). The optical transparency was measured by UV-vis spectrophotometer. Finally, the electrical properties, based on measured resistivity, were studied by four-point probe. The result showed that the ZrN films were all well orientated in the (111) plane. When the film thickness was increased, the grain size was also increased. The effect of the film thickness was observed in the charge in colors and optical transmission of the films.

Characterization of ZrN Thin Films Deposited by Reactive DC Magnetron Sputtering

In the past decade, many transition metal nitride thin films, especially titanium nitride (TiN) and zirconium nitride (ZrN), have been widely used as hard coatings, decorative coatings, diffusion barriers in IC technology and heat mirrors, as a result of their attractive properties of high hardness, corrosion resistance, thermal stability and electrical resistivity [1-4]. However, the ZrN films have shown significant performance regarding to its higher hardness, better corrosion resistance, lower electrical resistivity and warmer golden colour compared to those of the TiN films. ZrN films have shown significant performance advantages over TiN films [5-.

Structural, mechanical, electrical and wetting properties of ZrNx films deposited by Ar/N2 vacuum arc discharge: Effect of nitrogen partial pressure

Non-stiochiometric zirconium nitride (ZrNx) thin films have been deposited on silicon substrates by vacuum arc discharge of (N2+Ar) gas mixtures at different N2 partial pressure ratio. The microstructure, mechanical, electrical and wetting properties of these films are studied by means of X-ray diffraction (XRD), micro-Raman spectroscopy, Rutherford back scattering (RBS) technique, conventional micro-hardness testing, electrical resistivity, atomic force microscopy (AFM) and contact angle (CA) measurements. RBS results and analysis show that the (N/Zr) ratio in the film increases with increasing the N2 partial pressure. A ZrNx film with (Zr/N) ratio in the vicinity of stoichiometric ZrN is obtained at N2 partial pressure of 10%. XRD and Raman results indicate that all deposited films have strained cubic crystal phase of ZrN, regardless of the N2 partial pressure. On increasing the N2 partial pressure, the relative intensity of (111) orientation with respect to (200) orientation is seen to decrease. The effect of N2 partial pressure on micro-hardness and the resistivity of the deposited film is revealed and correlated to the alteration of grain size, crystallographic texture, stoichiometry and residual stress developed in the film. In particular, it is found that residual stress and nitrogen incorporation in the film play crucial role in the alteration of micro-hardness and resistivity respectively. In addition, CA and AFM results demonstrate that as N2 partial pressure increases, both the surface hydrophobicity and roughness of the deposited film increase, leading to a significant decrease in the film surface free energy (SFE).

Effect of nitrogen flow ratio on structure and properties of zirconium nitride films on Si(100) prepared by ion beam sputtering

In this study, zirconium nitride thin films were deposited on Si substrates by ion beam sputtering (IBS). Influence of N2/(N2+Ar) on the structural and physical properties of the films has been investigated with respect to the atomic ratio between nitrogen and zirconium. It was found that the thickness of layers decreased by increasing the F(N2). Moreover, crystalline plane peaks such as (111), (200) and (220) with (111) preferred orientation were observed due to strain energy which associate with (111) orientation in ZrN. Also, the fluctuation in nitrogen flow ratio results in colour and electrical resistivity of films.

Influence of substrate bias on microstructure and morphology of ZrN thin films deposited by arc ion plating

Zirconium nitride thin films were fabricated using arc ion plating under negative substrate biases to investigate the influence of substrate bias on the ZrN films. The phase, composition, and surface morphology of the ZrN ?lms, with respect to substrate bias, were studied by XRD, EPMA, and FE-SEM, respectively. The results show that cubic ZrN and hexagonal Zr phases form in the ZrN films. The competition between surface energy and strain energy makes the preferred orientation change from (111) to (200) and then back to highly (111) preferred orientation as a function of substrate bias. With the increase of bias voltage, the crystallite size of ZrN films reduces from 30 to 15 nm. Meanwhile, the film microstructure evolves from an apparent columnar structure to a highly dense equiaxed structure, indicating that the ion bombardment enhanced by substrate bias can suppress the columnar growth in the ZrN films. Deposition rate and mole ratio of Zr to N increase with the increase of bias voltage and reach the maximum at –50 V, and then show a decline trend when bias voltage further increases.

Nanomechanical and electrochemical properties of ZrN coated NiTi shape memory alloy

Zirconium nitride (ZrN) thin films were deposited on NiTi and Si substrates in the 23–570°C temperature range by direct current reactive magnetron sputtering using N2/Ar gas mixture. The film hardness, corrosion behavior, phase composition, and texture were determined. The deposited films were composed mainly by the cubic ZrN phase, whose texture varies with substrate temperature, changing progressively from (111) to (200) texture as the temperature increases. The hardness of the films is influenced by the texture and has a linear relationship with the ratio of the texture coefficients P(111)/P(200). The higher hardness is obtained for ZrN thin films with (200) texture. Electrochemical tests show that NiTi coated with (200)-oriented ZrN films has higher tendency to passivation and greater stability of the passive film as compared to (111)-oriented ZrN films, despite no abrupt changes was observed when the texture changes from (111) to (200).

Heating Effect on the Qualities of Cr-Zr-N Thin Films by Increasing in Zr Sputtering Current

Chromium zirconium nitride (Cr-Zr-N) thin films have been prepared by reactive dc closed field unbalanced magnetron co-sputtering on Si (100) wafers without external heating and voltage biasing. Heating effect on chemical composition, microstructure, and adhesion of the films by increasing in Zr sputtering current was investigated by using field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX). The results suggested that heating in the film and substrate during the deposition with high Zr target current was caused by bombarding the growing film with high energetic particles. From EDX analysis, the decrease of N content could be an effect of nitrogen desorption caused by heating and bombarding of high energetic particles. FE-SEM cross-sectional morphology revealed that grain refinement by Zr addition and high atomic diffusivity on both surface and bulk by heating and bombarding of high energetic particles resulted in denser fibrous grain microstructure. However, the increase of Zr target current leaded to the film with high compressive stress and could affect the film adhesion.

Variation of color in Zirconium nitride thin films prepared at high Ar flow rates with reactive dc magnetron sputtering

This study is to evaluate a color variation of the zirconium nitride thin film deposited at N2 flow rates in the range of 0.0 to 6.0sccm, whereas the high Ar flow rate is fixed at 6sccm. The thin films were deposited on unheated silicon wafer (100) with a reactive DC magnetron sputtering. The deposition current and deposition time were 0.6 A and 15 minutes, respectively. The color of films was measured using a spectrophotometer on CIE L*a*b* color index. The surface morphology and thickness of the films were investigated by atomic force microscopy (AFM). The structure was characterized by X-ray diffraction (XRD). The XRD results reveal the structures changes of film system from α-Zr, α-ZrN0.28, ZrN, Zr3N4 and finally amorphous with the increasing of N2 flow rate. The average film thickness was varied from a minimum value of 85.8nm to a maximum value of 276.0nm. In the study, colors of the deposited film were changed from silver, dark brown, brown and to blue. Interestingly, it was found that no golden color zirconium nitride film were obtained under the interested conditions.

Structure and Surface Morphology of Cr-Zr-N Thin Films Deposited by Reactive DC Magnetron Sputtering

In this study, chromium zirconium nitride (Cr-Zr-N) thin films have been prepared by reactive dc closed field unbalanced magnetron co-sputtering on Si (100) wafers and glass slides for 60min without substrate heating and biasing voltage in gas mixture of Ar and N2 with flow rates kept constant at 3.0sccm and 6.0sccm, respectively. The sputtering currents applied to Zr target were varied from 0.2 A to 0.8 A, whereas the current of Cr target was kept at 0.8 A. To investigate films structure and surface morphology as a function of Zr content, the as-deposited films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDX). The results suggested that increasing in current applied to Zr target enhanced the deposition rate and also increased Zr content in the films ranging from 6.0 to 31.2 at %. The films formed a solid solution (Cr, Zr)N where Zr atoms substitute Cr atoms in the CrN lattice. The lattice parameters increased from 0.4207nm to 0.4357nm, whereas the grain sizes decreased from 11.27nm to 7.412 nm. The film structure developed with the coexistence of (111) and (200) crystallographic orientation into a mixture of nanocrystalline grains as the sputtering currents of Zr target exceeded 0.2 A. The AFM images showed smoothing surface morphology with the roughness decreased from 9.471nm to 2.437nm. Cross-sectional micrographs exhibited the microstructure evolution corresponding to the grain refinement as a result of increasing Zr discharge current.

Variation of Color in Zirconium Nitride Thin Films Prepared by Reactive DC Magnetron Sputtering

This study is to evaluate a color variation of the zirconium nitride thin film, prepared from deposition technique of different N2 flow rates, ranging from 0.0 to 3.0 sccm, whereas the Ar flow rate is fixed at 3 sccm. The thin film was deposited on an unheated silicon wafer (100) via a reactive DC magnetron sputtering. The deposition current and deposition time were 0.6 A and 15 minutes, respectively. In the study, colors of film were changed from silver, gold, dark brown, brown, purple, pink to blue, when N2 flow rate further increase. Interestingly, the results indicate that gold color occurs in a very small interval of N2 flow rate.