Deposition Of Nickel Films Research Articles

Adhesive Strength of Ni–Cu Surface Alloy Formation by Low-Energy High-Current Electron Beam

The paper presents the adhesive strength measurements of the Ni–Cu surface alloy formed on a copper substrate at a different thickness of the transition layer. The formation of the surface alloy is provided by the low-energy high-current electron beam of a microsecond duration; the different thickness of the transition layer is varied by the thickness of the nickel film sputtered. The multiple deposition-irradiation process is performed during one vacuum cycle. It is found that the cross-section of the film (Ni)-substrate (Cu) interface is rather developed and curved. The transition layer thickness reduces with increasing thickness of the deposited nickel film. Scratch testing shows that the adhesive strength of the Ni–Cu surface alloy obtained by using the low-energy high-current electron beam, is higher than that of the sputter-deposited surface alloy. The highest adhesion is observed for the Ni–Cu surface alloy obtained by the nickel film deposition 0.125 μm thick. In this case, the crack formation and localized film delamination occur under the critical loads of 15 and 17 N, respectively. Nevertheless, a complete delamination of the surface alloy is not observed.

Effect of Substrate Grain Size on Structural and Corrosion Properties of Electrodeposited Nickel Layer Protected with Self-Assembled Film of Stearic Acid.

In the present study, the impact of copper substrate grain size on the structure of the succeeding electrodeposited nickel film and its consequent corrosion resistance in 3.5% NaCl medium were evaluated before and after functionalization with stearic acid. Nickel layers were electrodeposited on two different copper sheets with average grain size of 12 and 25 µm, followed by deposition of stearic acid film through self-assembly. X-ray diffraction analysis of the electrodeposited nickel films revealed that the deposition of nickel film on the Cu substrate with small (12 µm) and large (25 µm) grains is predominantly governed by growth in the (220) and (111) planes, respectively. Both electrodeposited films initially exhibited a hydrophilic nature, with water-contact angles of 56° and <10°, respectively. After functionalization with stearic acid, superhydrophobic films with contact angles of ~150° were obtained on both samples. In a 3.5% NaCl medium, the corrosion resistance of the nickel layer electrodeposited on the copper substrate with 25 µm grains was three times greater than that deposited on the copper substrate with 12 µm grains. After functionalization, the corrosion resistance of both films was greatly improved in both short and long immersion times in 3.5% NaCl medium.

Nickel Film Deposition with Varying RF Power for the Reduction of Contact Resistance in NiSi

In this study, the effect of radio frequency (RF) power on nickel (Ni) film deposition was studied to investigate the applications of lowering the contact resistance in the NiSi/Si junction. The RF powers of 100, 150, and 200 W were used for the deposition of the Ni film on an n/p silicon substrate. RMS roughnesses of 1.354, 1.174 and 1.338 nm were obtained at 100, 150, and 200 W, respectively. A circular transmission line model (CTLM) pattern was used to obtain the contact resistance for three different RF-power-deposited films. The lowest contact resistivity of 5.84 × 10−5 Ω-cm2 was obtained for the NiSi/n-Si substrate for Ni film deposited at 150 W RF power.

Catalyst Enhanced Chemical Vapor Deposition of Nickel on Polymer Surface

Catalyst enhanced chemical vapor deposition of nickel film on high Tg polymers such as teflon (PTFE), polyimide(PI), and polysulfone(PS) was investigated by hot wall and cold wall CVD, in which Ni(dmg)2, Ni(acac)2, Ni(hfac)2, Ni(TMHD)2, and Ni(cp)2 are used as precursors, and palladium complexes are used as catalysts. The films obtained were shiny with silvery color. The Ni was metallic and the purity of Ni was about 92%-95% from XPS analysis. SEM micrographs show that the film had good morphology. The conductivity of the film was about 0.5-4 Ω·cm-1. Ni films had good adhesion with polyimide and polysulfone.

Nanostructured Nickel Film Deposition on Carbon Fibers for Improving Reinforcement-matrix Interface in Metal Matrix Composites

The issues in dispersing any form of carbon in metal matrix is the major problem in the field of metal matrix composites with carbon reinforcement (MMCcr). The low wettability of carbon in molten metals and the difference in density are some of the difficulties to obtain a good dispersion of carbon fibers in the matrix and, as a consequence, an improvement of some critical properties for metals in a wide range of application (mechanical properties, electrical properties, optical properties). For this reason, the aim of this work is to obtain a metallic coated carbon fiber to enhance the interaction between the reinforcement and the matrix. Moreover, also the density of carbon fibers could be adjusted depending on the thickness of the coating. Electroless Nickel-Phosphorus Plating (ENP) is one of the candidate to be a coating technique to improve the interaction between the carbon fibers and the metal matrix. Despite of its versatility in terms of complex geometry of the substrate and homogeneity and adhesion of the coating, the presence of the phosphorus in the alloy could create some problems with the metal matrix such as the formation of metal-phosphorus products that can drastically decrease the mechanical properties of the composite. For this reason, in this work, is presented a new way of Electroless Pure Nickel Plating (EPP) without any introduction of phosphorus in the nickel coating. The dependence of the coating thickness and the density of the coated fibers were studied under different plating parameters (temperature of the plating solution, deposition rate and plating solution composition). All the samples were characterized with SEM and XRD and the thickness, density and homogeneity were compared for all the samples obtained.

Displacement deposition of gold nanoparticles and electroless deposition of nickel films on silicon-carbide (4H-SiC) wafers

Metallisation of silicon carbide (SiC) wafers is a key technology for producing efficient power devices. Conventional autocatalytic electroless deposition cannot produce adherent metal films directly on SiC substrates. The authors applied their recently developed surface-activation process for electroless metal-film deposition on silicon wafers to SiC wafers. Gold nanoparticles were produced on 4H-SiC substrates by displacement deposition after immersing the substrates in a tetrachloroauric(III) acid solution that includes hydrofluoric acid or potassium hydroxide. The size and the particle density of the deposited gold are changed with deposition parameters such as the surface condition of the substrates, the solution composition, and the UV-light illumination. The gold nanoparticles work not only as catalysts to initiate autocatalytic electroless deposition but also as binding-points between the metal film and the SiC surface. Adherent and uniform nickel-phosphorus alloy films are produced on such SiC substrates by autocatalytic electroless deposition without any further treatments.

Well-aligned NiSi/Si heterostructured nanowire arrays as field emitters

Nickel silicides are promising candidates in modern semiconductor devices as contact metals, metal gate electrodes, and source/drains in field effect transistors. A multistep template replication process was utilized to fabricate highly periodic and well-aligned silicon nanowires (SiNWs), and the size could be further reduced via dry oxidation and post chemical treatment. NiSi/Si heterostructured nanowire arrays were fabricated by nickel film deposition on SiNWs and then rapid thermal annealing at 550 °C. Field emission (FE) measurements illustrated that the turn-on field and field enhancement factor β of NiSi/Si heterostructures were 1.3 V/μm and ∼9000, better than that of the SiNWs, which were about 1.9 V/μm and ∼3900. These results are superior to the FE properties of other silicon-based nanomaterials. The excellent FE characteristics are attributed to the uniformly distributed nanowires with high aspect ratio and large proximity, high conductivity of uniform NiSi coating, and favorable morphological features with sharp and rough tips as hot emission spots. The single-crystalline silicon nanowires shelled with polycrystalline NiSi provide substantial opportunities for integration with Si devices to form active field emitters, and for exploration of the nickel silicides on other electrical and optical properties.

Electrochemical impedimetric biosensor based on a nanostructured polycarbonate substrate.

This study integrates the techniques of nanoelectroforming, hot-embossing, and electrochemical deposition to develop a disposable, low-cost, and high sensitivity nanostructure biosensor. A modified anodic aluminum oxide barrier-layer surface was used as the template for thin nickel film deposition. After etching the anodic aluminum oxide template off, a three-dimensional mold of the concave nanostructure array was created. The fabricated three-dimensional nickel mold was further used for replica molding of a nanostructure polycarbonate substrate by hot-embossing. A thin gold film was then sputtered onto the polycarbonate substrate to form the electrode, followed by deposition of an orderly and uniform gold nanoparticle layer on the three-dimensional gold electrode using electrochemical deposition. Finally, silver nanoparticles were deposited on the uniformly deposited gold nanoparticles to enhance the conductivity of the sensor. Electrochemical impedance spectroscopy analysis was then used to detect the concentration of the target element. The sensitivity of the proposed scheme on the detection of the dust mite antigen, Der p2, reached 0.1 pg/mL.

Effect of catalyst for nickel films for NiSi formation with improved interface roughness

Iodine is an effective catalyst to obtain homogeneous and smooth metal films with good interface properties. We adopted an iodine catalyst during the nickel film deposition by using atomic layer deposition (ALD) with bis(1-dimethylamino-2-methyl-2-butoxide)nickel [Ni(dmamb) 2] precursor and hydrogen reactant gas. The effect of iodine catalyst to nickel nucleation process was studied. The deposited films were silicided by rapid thermal process (RTP) which was performed by varying temperature from 400 °C to 900 °C in nitrogen ambient. The crystalline properties of nickel and nickel silicide films were examined by X-ray diffractometer (XRD) with various deposition temperatures. The interface properties and the surface morphology of nickel silicide films were studied by using Auger electron spectroscopy (AES) depth profile analyses and scanning electron microscopy (SEM). The experimental results showed that the iodine-catalyzed silicide film, which have a clean and smooth interface, exhibit lower resistivity, and lower leakage current density compared to that of non iodine-catalyzed films in implemented n +/p junction diode.

Synthesis of Carbon Nanotubes and Nanofibers by Thermal CVD on SiO&lt;SUB&gt;2&lt;/SUB&gt; and Al&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt; Support Layers

In this work, catalytic thermal chemical vapor deposition method, using a mixture of methane and hydrogen at atmospheric pressure in a horizontal tubular quartz furnace, was used to grow carbon nanostructured materials. Silicon wafers with SiO2 or Al2O3 layers were used as support for thin nickel film deposition used as catalyst. It has been shown that the interaction between catalysts and substrates is of critical importance for carbon nanotube growth. However, this mechanism is not completely understood. Here, the interaction between catalyst nickel film and two different oxide layers supported on silicon wafers was studied as well as the influence of both support systems (SiO2/Si and Al2O3/Si) on the carbon nanostructures growth at different temperatures and process running times. The substrates were characterized by atomic force microscopy and the carbon nanostructured materials were studied by Raman spectroscopy, high resolution scanning and transmission electron microscopy. At higher temperatures it was observed a high density of carbon nanotubes grown over Al2O3 support layer when compared to SiO2 support layer showing a different behavior for Ni catalyst on each of the substrates. A quite different Ni catalyst behavior was observed at lower temperatures due to the formation of carbon nanofibers instead of carbon nanotubes on both substrates.

Nickel Silicide Nanostructures Transformed from Site-Specific Silicon Nanostructures

An approach was proposed for fabricating nickel silicide nanostructures by self-aligned transformation from site-specific silicon nanostructures on the silicon-on-insulator substrate. The silicon nano-structures were firstly fabricated through the sequence of electron beam lithography and pattern transfer to silicon with reactive ion etching. The line-width of structures was shrunk by focused ion beam milling technology. Then nickel silicide nanostructures with the line-width of less than 50 nm were obtained on the insulator separation layer by sequential processes of nickel film deposition, rapid thermal annealing and wet-chemical etching. It was shown that 550 degrees C was an optimal annealing temperature to form NiSi nanostructures with low resistivity of about 15 microOmega.cm. As-formed metallic NiSi nanowire showed stable electrical properties at elevated temperature.

Concentration profiles during films deposition from a low-energy ion beam

An ion beam is described in the diffusion approximation, and a mathematical model of thin-film deposition process is developed. The volume profiles of concentration of components during nickel film deposition on a copper substrate are calculated for ion energies of 100, 200, and 400 eV and ion flux densities I = 1015, 1016, and 1017cm−2·s−1. The deposition model parameters are estimated using programs SUSPRE and SRIM. The concentration profiles of the components are compared for the corresponding numerical values of the model parameters.

Mechanism of Ni Film CVD with a Ni(Ktfaa)2 Precursor on a Silicon Substrate

AbstractThe mechanisms of pyrolysis in He and reduction in H2 of the Ni(ktfaa)2 chelate, and nickel film deposition on silicon substrates are discussed. The Ni films produced by CVD with the Ni(ktfaa)2 chelate as a precursor are clustered. At temperatures of 310 °C and higher pyrolysis of the Ni(ktfaa)2 chelate takes place. The hydrogen atmosphere provides a decrease in the reaction temperature to 242 °C. A decrease of the reduction temperature of the Ni(ktfaa)2 chelate on silicon substrates can take place if the OH groups have been adsorbed on the surface. The mechanisms of the chelate decomposition and film deposition define structure, morphology, and adhesion properties of the metallic nickel films. At temperatures higher than 310 °C the carbon‐containing by‐products are incorporated into the deposited Ni phase. The chemical activation of the silicon surface by prior metal atom introduction creates good adhesion and uniformity of nickel films deposited from the Ni(ktfaa)2 precursor.

Mechanism of Ni Film CVD with a Ni(ktfaa)2 Precursor on a Copper Substrate

AbstractThe mechanisms of pyrolysis in He and reduction in H2 of a Ni(ktfaa)2 chelate and nickel film deposition on copper substrates are discussed. The Ni films produced by CVD with the Ni(ktfaa)2 chelate as a precursor are continuous. Pyrolysis of the Ni(ktfaa)2 chelate takes place above 300 °C. The hydrogen atmosphere allows the reaction temperature to be decreased to 213 °C, but the film deposition rate is low. 300 °C is the optimal temperature for continuous Ni film deposition on Cu substrates. The mechanism of hydrogen interaction with the adsorbed Ni(ktfaa)2 chelate is discussed.

Determination of vapour pressure and standard enthalpies of sublimation and vapourisation of N,N$prime;-ethylenebis(2,4-pentanedion-iminoato)nickel(II) by a TG-based transpiration method

In order to identify a volatile metallo-organic precursor for the deposition of nickel films for CVD applications, equilibrium vapour pressure ( p e ) measurements were carried out on a N , N ′-ethylenebis(2,4-pentanedion-iminoato)nickel(II) (Ni[(acac) 2 en]) by employing a TG-based transpiration method over the range 406 to 495 K leading to values of 118.0±4.1 and 83.3±3.8 kJ mol −1 for the standard enthalpies of sublimation and vapourisation, respectively of Ni[(acac) 2 en]. From the plot of log p e against 1/ T , the melting point was derived to be 463 K, which is in reasonable agreement with 469±3 K reported in the literature and was also observed in DTA and melting point studies.

Determination of vapour pressure and standard enthalpies of sublimation and vapourisation of N, N′-ethylenebis(2,4-pentanedion-iminoato)nickel(II) by a TG-based transpiration method

In order to identify a volatile metallo-organic precursor for the deposition of nickel films for CVD applications, equilibrium vapour pressure ( p e) measurements were carried out on a N, N′-ethylenebis(2,4-pentanedion-iminoato)nickel(II) (Ni[(acac) 2en]) by employing a TG-based transpiration method over the range 406 to 495 K leading to values of 118.0±4.1 and 83.3±3.8 kJ mol −1 for the standard enthalpies of sublimation and vapourisation, respectively of Ni[(acac) 2en]. From the plot of log p e against 1/ T, the melting point was derived to be 463 K, which is in reasonable agreement with 469±3 K reported in the literature and was also observed in DTA and melting point studies.

Fabrication of n-type 4H–SiC/Ni junctions using electrochemical deposition

We report on the electrochemical deposition of nickel films on n-type 4H–SiC. High quality nickel films were prepared by a double potential pulse method. The as-deposited n-SiC/Ni junctions were rectifying with a barrier height of about 1.8 eV. The contact was converted to an ohmic junction by annealing at 950 °C in a 10% H2/N2 atmosphere.

Precursors and operating conditions for the metal-organic chemical vapor deposition of nickel films

The different precursors that have been tested or that are actually in use for the processing of thin films of nickel by the chemical vapor deposition technique are reviewed. Applications of thin films of nickel are presented. Deposition conditions and characteristics of the films obtained from different precursors are detailed. Ni(CO) 4, NiCp 2, Ni(MeCp) 2, Ni(hfa) 2, Ni(dmg) 2, and Ni(den) 2 appear as the most promising ones. The final choice of a precursor for the MOCVD of Ni films depends on requirements concerning the process (e.g. safety issues, deposition temperature, growth rate) and the purity of the deposited films.

Crystal orientation and microstructure of nickel film deposited at liquid nitrogen temperature by sputtering

Sputter deposition of nickel films at liquid nitrogen temperature was performed to clarify the effects of the surface migration of the deposited atoms. The film deposited at liquid nitrogen temperature and low Ar gas pressure had excellent (111) orientation and good crystallinity. Therefore, deposition at a low-temperature and low Ar gas pressure is a useful technique for obtaining film with excellent crystal orientation of the closest packing plane. Ion bombardment of the film surface during deposition at liquid nitrogen temperature led to a large degradation of the film crystallinity, but it had quite the opposite effect at room temperature, i.e., it promoted the (111) orientation of the film and improved the crystallinity of the film. These results indicate that the ion bombardment produced defects in the crystallites at a low temperature where migration of the deposited atoms was limited.