Nickel-chromium Films Research Articles

Multi-parameter coupling study of magnetron sputtering nickel–chromium thin film based on Taguchi-gray correlation method

In this study, a nickel–chromium film for detecting strain stress was deposited on 304 stainless steel substrates by the magnetron sputtering technique. The sputtering process parameters were optimized to obtain a better nickel–chromium film. Orthogonal array L16(44) design, signal-to-noise ratio calculation, and variance analysis were performed on the experimental data by the Taguchi method. The influence of the coupling of process parameters such as power, pressure, bias, and substrate temperature on the surface roughness, deposition rate, and resistivity of the film was studied. The power is the most significant influence factor affecting the film’s performance indicators, and the contribution rates of each process parameter to the response variables and the regression equation of each response variable are obtained. Finally, the gray correlation analysis results of the response variables show that at conditions of 200 W power, 1.6 Pa pressure, −100 V bias, and 400 °C substrate temperature, the surface roughness of the nickel–chromium film is 55 nm, the deposition rate is 110 nm/min, and the resistivity is 1.10 × 10−4 Ω cm. It can be seen that the best film performance parameter group can be obtained using the Taguchi gray correlation method under the multi-parameter coupling of the nickel–chromium thin-film.

Development of SiO2/TiO2/Al2O3-based/TiO2 coating for preventing sulfide corrosion in thermal power plant boilers

In thermal power generation equipment, wall thinning on boiler tubes due to sulfide corrosion has been a problem. The methods for resolving or preventing the problem are coating of a nickel-chromium film by plasma spraying, weld cladding, and replacement of water wall tubing. These methods are expensive and time consuming. Therefore, an economical and straightforward coating technique was developed for preventing sulfide corrosion on boiler tubes. The developed coating has a four-layered structure comprising, in order from the boiler tube substrate, thin films of (1) a SiO2 layer, (2) a TiO2 layer, (3) an Al2O3-based layer, and (4) a TiO2 layer. The coating reduced corrosion to 25% or less compared with an uncoated part under a simulated condition (Gas: CO2/H2/N2/CO/H2O = 12%/4%/67%/8%/9% H2S 330 ppm, Temperature: 500 °C). It was found that the coating on boiler tubes is exceptionally durable and continues to be effective for more than 2 years in actual power plants. This coating process can be applied to a large area, and the work period is short. When the coating area is 100 m2, the working time is 3 days and total spraying time is only 7 h.

Structure design and optimization for a cutting force measurement tool with embedded nickel–chromium film sensor

The cutting force generated during the cutting process affects the quality of the workpieces and tool wear. Accurate real-time monitoring of cutting forces plays an important role in the study of cutting mechanism and machining quality improvement. This article describes a tool with embedded nickel–chrome thin film sensor for cutting force measurement. The tool structure is optimized with grooving, drilling to form stepped sidewalls in the appropriate position. A simplified cantilever model for finite element simulation analysis in mechanics is used for analysis, in which the substrate thickness and Ni-Cr thin film–resistive grid position are determined through analysis. The output voltage is proportional to the external force with a factor of 0.0091 at 0.2 mm substrate thickness, which is a 100% gain over the original model. The designed tool with embedded sensors fabricated on the 0.5 mm substrate was validated with static calibration and cutting test. The results demonstrate that the sensor output voltage is proportional to the external force with a scale factor of 0.00518 and the resistance grid factor of 1.6. The tool and the Kistler dynamometer are in good agreement, with an error of 6.8% in measuring the main cutting force.

Investigation of percolation thickness of sputter coated thin NiCr films on clear float glass

Percolation thickness of reactively sputtered nickel chromium (NiCr) thin films is reported in this study. Nickel-chromium films with the thicknesses in between 1 and 10nm were deposited on 4mm clear glass substrate by dc magnetron sputtering. Optical properties such as refractive index, extinction coefficient and also sheet resistance, carrier concentration and mobility of NiCr films were determined by a combination of variable-angle spectroscopic ellipsometry and four point probe measurements. We show both the percolation phenomena in atmosphere and critical percolation thickness for thin NiCr films by both electrical and optical techniques. The two techniques gave consistent results with each other.

Terahertz absorption characteristics of nickel–chromium film in a microbolometer focal plane array

Nickel-chromium (NiCr) thin film acted as a terahertz (THz) absorption layer in uncooled infrared (IR) microbolometers operated in the THz spectral range. Nanoscale NiCr thin films with different thicknesses were deposited on the diaphragms of 320 × 240 IR focal plane arrays (IRFPAs). The experiments suggested that the THz absorption of NiCr film increased with the increased frequency. Absorption for a lower frequency decreased whereas that for a higher frequency increased with the decreased film thickness. Optimised absorption for different spectral ranges was achieved by adjusting the NiCr film thickness. A 30 nm NiCr film provided the largest absorption in 0.5-1.5 THz whereas an 8 nm NiCr film showed the greatest contribution in 2-2.5 THz. The THz absorption characteristics of the pixel membrane structure in the IRFPAs coupled with a thin metallic film were modelled and analysed. A good agreement was obtained between the calculations and the measurements.

Photochemistry of bistriphenyl phosphine nickel dicarbonyl on silicon surfaces: the lithographic deposition of nickel and nickel-iron, nickel-chromium and iron-chromium containing films

The photolysis of Ni(CO)2(PPh3)2 as surface films on silicon surfaces has been investigated. The photolysis of the title complex leads to the loss of ligand from the coordination sphere and the formation of nickel. The ligands are largely lost to the gas phase although impurity originating from the triphenylphosphine ligand remains within the film. The controlled construction of films formed from a mixture of Ni(CO)2(PPh3)2 and Cr(CO)5PPh3 could be accomplished by spin coating from a solution containing both precursors. Photolysis of films composed of a mixture of Ni(CO)2(PPh3)2 and Cr(CO)5PPh3 resulted in the formation of a nickel-chromium film. In a similar fashion films constructed from of Ni(CO)2(PPh3)2 and Fe(CO)4PPh3 could be photolysed to generate films of nickel-iron and films composed of Cr(CO)5PPh3 and Fe(CO)4PPh3 could be photolysed to generate films of chromium-iron. Both of these films contained impurities associated with remnant triphenylphosphine and oxidation of the surface. This process was shown to be compatible with standard lithography techniques by the lithography of 2 μm lines of triphenylphosphine contaminated nickel on a silicon surface.

Seebeck measurements of rf sputtered nickel-chromium films

Thin films of nickel-chromium alloys (10% chromium) were produced by the radio-frequency (rf) sputtering technique. The Seebeck coefficient of these films was measured with a constant 10 °C differential up to 360 °C versus bulk Alumel wires. At higher sputtering power (400 w) with a water-cooled anode, the seebeck coefficient approached the bulk response to within 2-1/2%. At lower sputtering powers, oxygen was incorporated into the lower density films, causing a decrease in thermal emf. Depositions made at elevated anode temperatures also showed a degradation in thermal emf, probably due to increased film oxidation with temperature.

3125. Seebeck measurements on rf sputtered nickel-chromium films

3125. Seebeck measurements on rf sputtered nickel-chromium films

Flight quality nickel-chromium films with sheet resistances up to 420 ohms per square : T. J. Faith and J. W. Jennings. Microelectron. and Reliab14, 41 (1975)

Thin films of lithium phosphorus oxynitride (Lipon) have been grown using a plasma-assisted, directed vapor deposition (PA-DVD) technique. In this approach, a high voltage electron beam is used to vaporize a Li3PO4 source and a supersonic, nitrogen-doped, helium gas jet then transport the vapor towards a substrate. A hollow cathode technique was then used to create an argon plasma just above the substrate. This sufficiently ionized the nitrogen in the gas jet to allow its incorporation into the Li3PO4 film reactively forming lithium phosphorus oxynitride. Increasing the nitrogen flux in the gas jet also increased the deposition rate from 113 to 178 nm min−1 for the deposition conditions used here, significantly reduced the pore volume fraction in the films and increased the N/P ratio from 0 to 0.75 as the gas jet nitrogen flux was increased from zero to 4.3 × 1018 molecules cm−2 s−1. Using substrate rotation, pore and columnar-free dense Lipon films could be grown by this method. The Li-ion conductivity increased from 3.7 × 10−9 to 5.2 × 10−7 S cm−1 as the nitrogen concentration was increased from zero to 2.1 × 1018 molecules cm−2 s−1 and was correlated with an increase in the film's Li/P ratio. An optimum nitrogen flux has been identified. As the nitrogen flux was increased above this value, the Lipon films suffered lithium loss and partial crystallization, resulting in a decrease in their Li-ion conductivity.

Flight quality nickel-chromium films with sheet resistances up to 420 ohms per square

Nickel-chromium films have been deposited with good reproducibility and reasonable uniformity of sheet resistance using a rudimentary evaporation technique. A standardized process flow has resulted in circuit yields of approx. 99 per cent for design values of sheet resistance up to 200 Ω/sq. and yields of 89 and 79 per cent for 260 and 325 Ω/sq., respectively. Circuits stabilized with (a minimum of) 2 hr air bake at 320°C have shown excellent resistor stability and reliability through packaging and environmental testing for design values up to 420 Ω/sq.

Trimming of nickel-chromium film resistors

This paper describes the development of a method for the accurate adjustment of thin film resistors to predetermined values. Diamond tip ultrasonic scribing techniques are outlined and experimental results are discussed showing how the wear on the tool tip may be utilised to produce high quality cuts. A comparison of diamond scribing, spark erosion and Laser cutting is made; each method is illustrated by scanning electron micrographs.

Composition and Electrical Properties of Nickel-Chromium Films

Composition and Electrical Properties of Nickel-Chromium Films

A study of electrical conduction in island structure nickel and 80:20 nickel-chromium films

The theory of conduction in discontinuous metal films proposed by Neugebauer and Webb has been amplified to take into account electron transfer between charged island species other than charged to neutral island transfers. The effect on the resistivity has been shown to be slight, but the predicted values of temperature coefficient of resistance agree more closely with experiment for films of nickel and nickel-chromium deposited at 2 × 10 -5 torr. It has not been possible to test the theory for films deposited at 7 × 10 -7 torr, because the large island and gap sizes found in these films either give films that are open circuit or that have near metallic behaviour.

Role of hydrogen in the sputtering of nickel-chromium films

Role of hydrogen in the sputtering of nickel-chromium films

Role of Hydrogen in the Sputtering of Nickel–Chromium Films

Mass-spectrometer analysis of the gases in a sputtering apparatus has demonstrated that: (1) Under normal sputtering conditions, copious quantities of hydrogen are evolved from the dissociation of adsorbed water vapor, and (2) hydrogen partial pressures as low as 5 × 10−7 Torr can measurably reduce sputtering rates in an argon discharge. These results have been used to develop a novel approach to thickness control of sputtered thin films. The techniques has been applied to the deposition of nickel–chromium films with a control on thickness of ±1%.

A study of evaporated nickel chromium films as potentiometer tracks

Evaporated nickel chromium films on glass and alumina substrates have been examined to ascertain their suitability for use as the resistance element of a variable resistor. Films on glass were found to have a life of the order of 10,000 cycles when worn by a light sliding contact; any electric current in the moving contact damaged the film reducing the life further. Films deposited on recrystallized alumina had better properties. A loading of the sliding contact of 1 mA at 45 V open circuit voltage produced no detectable electrical damage and under these conditions films withstood up to 10 6 cycles with little damage. It is proposed that the good wear resistant properties of nichrome films deposited on alumina result from strong adhesion of the film to a relatively unyielding substrate. The nature of the contact resistance is discussed.

A technique for measuring the temperature of nickel-chromium films in thin film circuits

A technique is described for measuring actual temperatures of thin nickel-chromium film resistors under static and dynamic loading conditions. The method, based on a resistance bridge, is sensitive to ±2°C and is suitable for evaluating thermal dissipation characteristics of substrate and encapsulating materials. Life test results obtained on standard nickel-chromium resistor films show a drift of parameters less than 0·01 per cent/1000 hr after 3000 hr at 100°C. This alloy system has been chosen for the resistive elements in thin film circuits, because of its chemical stability and the ease with which it can be deposited with reproducible characteristics. Thin film resistors of up to 100,000 Ω/cm 2 are now being manufactured from films deposited to 300 Ω/sq. sheet resistivity. The electrical properties of these films are different from those of the bulk material in two ways: (a) since the film thickness is comparable to the mean free path of the conduction electrons, the film resistivity is higher than the value calculated from the bulk resistivity of 10 −4 Ω-cm; and (b) the significant contributions to electrical conduction by tunnelling mechanisms, reduce the temperature coefficient of resistance from 400 ppm for the bulk material to 50 ppm in films. The characteristics of such films can be very accurately controlled by careful choice of the deposition conditions.

Thickness and composition of nickel-chromium films: H J Degenhart and I H Pratt, Trans 10 AVS Nat Vac Symp, MacMillan & Co, 1963, p 480.

Thickness and composition of nickel-chromium films: H J Degenhart and I H Pratt, Trans 10 AVS Nat Vac Symp, MacMillan & Co, 1963, p 480.

The structure of vacuum condensed Ni-Cr films

Vacuum depoaited 40–60 nickel-chromium films have been examined by electron diffraction and microscopy. The changes in structure and appearance with annealing temperatures up to 700°C are reported, and the results discussed relative to the stabilization of thin film evaporated resistors.

Vapor Deposited Thin Metal Film Resistor

The vapor deposited thin metal film is known to be different from the same bulk metal in its properties in many cases.Therefore, since the properties of the thin metal films are not obtainable from bulk metal directly, the thin metal film must be produced at first for perusing these properties.This paper briefly shows the process producing the thin metal resistive elements by the vapor deposition method and then presents the various characteristics obtained from the sample which are, the nickel-chromium and the chromium thin metal films deposited on the hot micro slide glass substrata. These samples are produced for the purpose of miniaturizating electronic components.These characteristics are summarized as follows(1) When the artificial aging by heating is given at 200°C, the resistance changes [ΔR/R (25°C)] of both the nickel-chromium and the chromium film increase rapidly with time up to 10 hours, then both of them show almost saturated characteristics. And it can be said for both nickel-chromium and chromium films that the resistance change are smaller for the thinner films.(2) When the artificial aging by heating is given at 300°C, the resistance changes versus time of both the nickel-chromium and the chromium films are such that the characteristics varies from semiconductor type to bulk-metal type as they become thicker. For the extremely thin films, they become open with considerably short time, and this peculiarity is likely to occur for the case of nickel-chromium films.(3) For the given value of resistance, the chromium film artificially aged by heating at 300°C shows smaller temperature coefficient than the chromium film aged at 200°C. As the matter of fact, the resistive element consisting of chromium film aged at 300°C, with the excellent temperature coefficient of 10-5/°C order for the temperature range of -42°C to +130°C was obtained in the experiment.On the other hand, for the nickel-chromium films, it may be concluded that the resistance elements having the almost zero temperature coefficient can be produced by adjusting the film thickness properly.(4) In the other tests such as the voltage dependency, resistance noise characteristics and resistance change before and after the temperature cycling etc., chromium film showed better results in comparison to nickel-chromium film.