MICROBRIDGE TESTING OF YOUNG'S MODULUS AND RESIDUAL STRESS OF NICKEL FILM ELECTROPLATED ON SILICON WAFER

Microbridge testing is used to measure the Young's modulus and residual stresses ofmetallic films. Nickel film microbridges with widths of several hundred microns arefabricated by Microelectromechanical Systems. In order to measure the mechanicalproperties of nickel film microbridges, special shaft structure is designed to solve theproblem of getting the load--deflection curves of metal film microbridge by Nanoin--denter XP system with normal Berkovich probe. Theoretical analysis of the micro--bridge load--deflection curve is proposed to evaluate the Young's modulus and residualstress of the films simultaneously. The calculated results based on the experimentalmeasurements show that the average Young's modulus and residual stress are around190GPa and 175MPa respectively, while the Young's modulus measured by Nano-hardness method on nickel film with silicon substrate is 186.8±7.34GPa.

Fabrication, lattice strain, corrosion resistance and mechanical strength of nanocrystalline nickel films

Nanocrystalline nickel films of 17-40 nm grain sizes were prepared using pulsejet electrodeposition. Structure, corrosion and lattice strain were analysed by transmission electron microscope, electrochemical workstation and X-ray diffraction, revealing that with decreasing of grain size, the lattice strain, corrosion rate of the films are enhanced. The observations can be consistently understood in terms of the bond-order-length-strength correlation mechanism indicating that the shortened and strengthened bonds between the under-coordinated atoms modify the energy density and the atomic cohesive energy in the surface skins of the grains. The surface energy density gain is responsible for the residual atomic cohesive energy for the activation energy of corrosion. Additionally, a novel algorithm was proposed to extract the elastic-plastic properties of nickel films and results that the nickel film has much higher yield strength than bulk nickel.

Catalyst Enhanced Chemical Vapor Deposition of Nano-Particle Nickel Films on Teflon Surface

Films formed with nanosized nickel particles on teflon surface were prepared by means of catalyst enhanced chemical vapor deposition （CECVD） with Ni（dmg）2, Ni（acac）2, Ni（hfac）2, Ni（TMHD）2, and Ni（cp）2 as precursors, and complexes Pd（hfac）2, PdC12 and Pd（η^3-2-methylallyl）acac as catalyst under cartier gas （H2）. The film growth rate depends on the precursors and substrate temperature. The chemical value, purity and surface morphology of the Ni particle films were characterized by X-ray photoelectron spectroscopy （XPS） and scanning electron microscopy （SEM）. The films obtained were shiny with silvery color, and consisted of grains with a particle size of 50-140 nm. The Ni was metallic of which the purity was about 90%-95% from XPS analysis. SEM micrograph showed that the film had good morphology.

Properties of fluoride film and its effect on electroless nickel deposition on magnesium alloys

The physical characteristics and microstructure of the fluoride film formed during activation were investigated using SEM,XPS and SAM,and its stability in electroless nickel(EN) bath was analyzed.The effects of the fluoride film on EN deposition were studied additionally.The results show that the fluoride film on magnesium alloys is a kind of porous film composed of MgF2 with thickness of 1.6-3.2 μm.The composition of the activation bath and pretreatment of EN processing have influence on the composition of the fluoride film.The fluoride is stable and dissolves little in EN bath;as a result,the fluoride film can protect magnesium substrate from the corrosion of EN bath.The composition of fluoride determines the initial deposition of EN and part of the fluoride film finally exists as inclusion in EN coating.

Electrochemically switched ion exchange performances of capillary deposited nickel hexacyanoferrate thin films

Thin films of capillary deposited nickel hexacyanoferrate(NiHCF) were investigated as electrochemically switched ion exchange(ESIX) materials. The films were generated on platinum and graphite substrates based on the ternary reagent diagram. In 1 mol/L KNO3 solution, cyclic voltammetry(CV) combined with energy-dispersive X-ray spectroscopy(EDS) was used to determine the influence of experimental conditions on the electroactivity of the NiHCF thin film on Pt substrates. The ion selectivity, ion-exchange capacity and the regenerability of NiHCF films on Pt and graphite substrates were investigated. The experiment results show that the NiHCF thin films from Ni2+-poor growth conditions have double peaks CV curves and contain relatively larger amount of potassium; while those from Ni2+-rich growth conditions are single peak CV curves and contain relatively smaller amount of potassium. It is demonstrated that the NiHCF thin films of capillary chemical deposition have good ESIX performances.

Preparations of TiO_2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.

Structural and Optical Dispersion Characterisation of Sprayed Nickel Oxide Thin Films

Crystalline and non-crystalline nickel oxide (NiO) thin films were obtained by spray pyrolysis technique (SPT) using nickel acetate tetrahydrate solutions onto glass substrates at different temperatures from 225 to 350℃. Structure of the as-deposited NiO thin films have been examined by X-ray diffraction (XRD) and atomic force microscope (AFM). The results showed that an amorphous structure of the films at low substrate temperature (Ts = 225℃), while at higher Ts ≥ 275℃, a cubic single phase structure of NiO film is formed. The refractive index (n) and the extinction coefficient (k) have been calculated from the corrected transmittance and reflectance measurements over the spectral range from 250 to 2400 nm. Some of the optical absorption parameters, such as optical dispersion energies, Eo and Ed, dielectric constant, ε, the average values of oscillator strength, So, wavelength of single oscillator λo and plasma frequency, ωp, have been evaluated.

XPS analysis of passive film formed on the G3 nickel-base alloy tubing under corrosive conditions

In the present study, the passive film formed on the G3 nickel-base alloy tubing under corrosive conditions including H2S ,CO2 ,and Cl-at 130 ℃ and 205 ℃ is studied with X-ray photoelectron spectroscopy（XPS）. The results reveal that the passive film formed at 205℃ consists of Cr, Ni, Fe, S and O elements and is over 470 nm in thickness. The passive film can be divided into three layers, the outer-layer is composed of NiS2 and Cr2 S3 , the intermediate-layer of Cr（OH） 3, Ni （OH） 2, NiS2, Cr2 $3 and a small quantity of NiO and Cr2 O3, and the inner-layer of NiO, Cr2 O3, and alloy elements. Due to the invasion of S2 - into the passive film and the decrease of the content of chromium oxide in the film, the corrosion resistance of the G3 alloy in the sour environment at 205 ℃ is weakened.

Investigation of ultrafast electron dynamics of nickel film and micro-nano-structure film

The electron thermalization and relaxation processes in ferromagnetic nickel thin film and micro-nano- structure film have been studied by measuring the transient change after excitation by a femtosecond laser pulse. The measurements indicate that the electron thermalization time is between 18 and 47 fs. This is somewhat faster than the value reported before. And the thermalization time of the micro-nano-structure film is much longer than the nickel film. We deduce that it is caused by the discontinuity of the electron band close to the Fermi level in the micro-nano-structure nickel film.

Influence of process parameters on electrochemical and physical properties of sputtered iron-doped nickel oxide thin films

The iron-doped nickel oxide films used as oxygen evolution catalysts in the photoelectrochemical production of hydrogen from solar energy were deposited by means of RF reactive magnetron sputtering from a Ni-Fe alloy target in oxygen and argon atmosphere.The effects of processing parameters on the film properties,such as overpotential,composition,surface morphology and preferred orientation,were investigated.The electrochemical experiment,structural and compositional measurements indicate that the relative lower substrate temperature,higher RF power,higher working pressure and oxygen content are necessary to gain lower overpotential.The lowest overpotential of 251 mV is obtained at a current density of 80 mA/cm2.The existence of iron,which acts as activity site,and Ni3+ ion is responsible for lowering overpotential.By analyzing SEM and XRD data,it is also noticed that an improvement in crystallinity,appropriate grain size and less crystalline phase contribute to an increased electrocatalytic activity in oxygen evolution reaction.These results mentioned above indicate that iron-doped nickel oxide is promising as an oxygen catalyst.

Molecular dynamics simulation of ion selectivity traits of nickel hexacyanoferrate thin films

The ion selectivity of nickel hexacyanoferrate thin film to alkali cations in ESIX (electrochemically switched ion exchange) processes was investigated using molecular dynamics(MD) techniques; water and cation (Na+ and Cs+) intercalation, configuration, and dynamics in reduced nickel hexacyanoferrate structures with different cation combinations were studied and compared with the experimental results. In the simulations, water was represented by an extended simple point-charge(SPC/E) model, and all other atomic interactions were represented by a universal force field(UFF). The potential energies of various cations combination (Cs+ and Na+) in reduced i-NiHCF and 1 mol/L Cs/NaCl mixed solution were obtained. In most cases, the total potential energy of the solid is reduced when water is intercalated into the various reduced NiHCF structures. Combining the solid and the solution simulation results, it is shown that the solid composition of 3Cs+/1Na+ is the stablest structure form (NaCs3Ni4[Fe(CN)6]3) over a range of solution compositions.

Effect of Nickel Distributions Embedded in Amorphous Carbon Films on Transport Properties

Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range of400-500 K shows the extended state conduction.The conductivity data in the temperature range of 150-300 K shows the multi-phonon hopping conduction.The Berthelot-type conduction dominates in the temperature range of 50-150 K.The conductivity of the films in the temperature range about 〈 50 K is described in terms of variable-range hopping conduction.In low temperatures,the localized density of state around Fermi level（F）for the film deposition with 3.92% nickel has a maximum value of about 56.2×10^（17）cm^（-3）eV^（-1） with the minimum average hopping distance of about 3.43 × 10^（-6） cm.

Electronic Properties of Passive Films Formed on G3 and G30 Nickel-based Alloys in Bicarbonate/Carbonate Buffer Solution

The electronic properties of passive films formed on G3 and G30 alloys in bicarbonate/carbonate buffer solution were comparatively studied by electrochemical impedance spectra（EIS） and Mott-Schottky analysis, the chemical composition of the passive film formed on G3 alloy was detected by X-ray photoelectron spectroscopy （XPS）. The results show that passive film on G3 alloy had better protection than that on G30 alloy. The transfer resistance, film resistance and diffusion resistance of the passive films on both alloys increased with increasing formation potential, prolonging formation time, increasing pH value, decreasing formation temperature, and decreasing chloride and sulphide ions concentration. Mott-Schottky plot reveals that the passive films on the two alloys show a p-n semi-conductive character. XPS analysis indicates that the passive film on G3 alloy was composed of an inner Cr oxide and an outer Fe, Mo/Ni oxides.

Field emission properties of a-C and a-C：H films deposited on silicon surfaces modified with nickel nanoparticles

The a-C and a-C：H films are deposited on silicon surfaces modified with and without nickel nanoparticles by using mid-frequency magnetron sputtering. The microstructures and morphologies of the films are analyzed by Raman spec- troscopy and atomic force microscopy. Field emission behaviors of the deposited films with and without nickel nanopar- ticles modification are comparatively investigated. It is found that the hydrogen-free carbon film exhibits a high field emission current density and low turn-on electric field compared with the hydrogenated carbon film. Nickel modifying could increase the current density, whereas it has no significant effect on the turn-on electric field. The mechanism of field electron emission of a sample is discussed from the surface morphologies of the films and nickel nanoparticle roles in the interface between film and substrate.

Structural and Surface Morphology Analysis of Nickel Phthalocyanine Thin Films

The thin films of Nickel Phthalocyanine (NiPc) on glass substrates were prepared by vacuum evaporation at different substrates temperatures (300, 325, 350, 400, 450) K. The structure and surface morphology of NiPc in powder and thin film forms (265 nm) were studied using X-ray diffraction and atomic force microscope (AFM), and showed that there was a change and enhance in the crystallinity and surface morphology due to change in the substrates temperatures. Analysis of X-rays diffraction patterns of NiPc in powder form showed that it had an α-polycrystalline phase with monoclinic system with lattice constants a = 1.513 nm, b = 0.462 nm, c = 2.03 nm and β = 123.46°. Thermal evaporation of NiPc at different substrates temperatures led to β-crystalline films oriented preferentially to the (100) plane with different substrate temperatures. The mean crystallite size increased with substrates temperatures from 300 K to 450 K. This result was supported by AFM measurements, which exhibited a relatively larger grain size.

Impact Thickness on Structural and Electrical Characterization of Nickel Phthalocyanine Thin Films

Thin films of Nickel Phthalocyanine have been prepared by evaporation technique for (50 - 350 nm) of thickness. XRD studies show that the thin films have single crystalline structure for low thicknesses with (100) orientation and the crystallite size increased with increased thickness. Also from the AFM technique for NiPc films, the roughness was determined and the grain size increases with increasing of thickness from except at thickness 350 nm. The studies of electrical properties, morphology and orientations of the crystallites are important to understand and predict the nature of the films and essential for their successful applications in solar cell and sensors. The electrical properties of these films were studied with different thickness, NiPc has three activation energy. Carrier’s concentration and mobility was calculated. Hall measurements showed that all the films are p-type.

Ni nanocomposite films formed by Ni nanowires embedded in Ni matrix using electrodeposition

Ni nanocomposite films formed by Ni nanowires embedded in Ni matrix(Ni nanowire/Ni composite films)were fabricated by electrodeposition combined with supersonic stirring in a conventional Watts'bath containing Ni nanowires with diameter about 30 nm.The deposition temperature-dependent microstructure,crystal orientation,lattice constant and corrosion behavior of the Ni nanowire/Ni composite films were investigated by field emission scanning electron microscope,X-ray diffraction and potentiodynamic polarization tests,respectively.And the possible mechanism was discussed.It is found that to some extent,the deposition temperature has an impact on the microstructure,crystal orientation,lattice constant and corrosion property of the Ni nanowire/Ni composite films.The Ni nanowire/Ni composite films prepared at 50℃exhibit a novel inter-twisted-nanowire microstructure and have the best corrosion resistance.

Synthesis and characterization of boron-doped NiO thin films pro-duced by spray pyrolysis

Boron-doped NiO thin films were prepared on glass substrates at 400℃ by airbrush spraying method using a solution of nickel nitrate hexahydrate. Their physical properties were investigated as a function of dopant concentration. From X-ray diffraction patterns, it is observed that the films have cubic structure with lattice parameters varying with boron concentration. The morphologies of the films were examined by using scanning electron microscopy, and the grain sizes were measured to be around 30-50 nm. Optical measurements show that the band gap energies of the films first decrease then increase with increasing boron concentration. The resistivities of the films were determined by four point probe method, and the changes in resistivity with boron concentration were investigated.

Optimized growth and dielectric properties of barium titanate thin films on polycrystalline Ni foils

Barium titanate（BTO） thin films were deposited on polycrystalline Ni foils by using the polymer assisted deposition（PAD） technique.The growth conditions including ambient and annealing temperatures were carefully optimized based on thermal dynamic analysis to control the oxidation processing and interdiffusion.Crystal structures,surface morphologies,and dielectric performance were examined and compared for BTO thin films annealed under different temperatures.Correlations between the fabrication conditions,microstructures,and dielectric properties were discussed.BTO thin films fabricated under the optimized conditions show good crystalline structure and promising dielectric properties with εr～ 400 and tan δ 〈 0.025 at 100 kHz.The data demonstrate that BTO films grown on polycrystalline Ni substrates by PAD are promising in device applications.

PHASE TRANSFORMATION BEHAVIOR IN THE SPUTTER DEPOSITED Ti-Pd-Ni THIN FILMS

Ti-Pd-Ni thin films were prepared by sputter deposition at room temperature. The as-deposited thin films were crystallized at 750°C followed by various cooling conditions, and the structural change emerging in the films was characterized by means of both X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It was found that the phase transformation temperatures of Ti50.6Pd30Ni19.4 ingot we much higher than those of its thin film. The B19' and B19 phases coexisted, together with the Ti2Ni type and Ti2Pd type of precipitates at the room temperature. Both the B19-B2 one-stage and the B19'-B19-B2 two-stage phase transformations took place when the films experienced thermal change across the region of phase transformation temperatures.