Properties Of Ag Films Research Articles

Dependence of the Generation Behavior of Charged Nanoparticles and Ag Film Growth on Sputtering Power during DC Magnetron Sputtering

Effects of sputtering power on the deposition rate and microstructure, crystallinity, and electrical properties of Ag films during direct current (DC) magnetron sputtering are investigated. Thin films (~ 100 nm) are deposited at sputtering powers of 10, 20, 50, 100, 200 and 300 W and analyzed by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and a four-point probe. The film deposited at a sputtering power of 10 W has the lowest growth rate, but the highest crystalline quality, with the lowest full width at half maximum (FWHM) and the lowest resistivity. The film deposited at a sputtering power of 200 W has the highest growth rate, and the second best crystalline quality in view of FWHM and resistivity. The film deposited at a sputtering power of 50 W has the moderate growth rate, and the worst crystalline quality in view of FWHM and resistivity. High-resolution TEM observations reveal that films deposited at sputtering powers of 10 and 200 W have far fewer defects, such as grain boundaries, dislocations and stacking faults than those deposited at a sputtering power of 50 W. Such deposition behavior could be explained by sputtering power, which affected the generation of the charged nanoparticles. And the high quality of films could be obtained at a high deposition rate, in which charge plays an important role.Graphic

Deposition of Ag and Au–Ag alloy nanoparticle films by spray pyrolysis technique with tuned plasmonic properties

Abstract Silver (Ag) and gold–silver (Au–Ag) alloy nanoparticle films have been prepared on the transparent substrates using a simple inexpensive spray pyrolysis technique. The surface plasmon resonance (SPR) properties of Ag films were investigated by varying spray solution volume. Also, the tunability of SPR properties using an electric field to the nozzle was demonstrated in this work. The reduced full width at half maximum and blue shift in the SPR band position were observed with ΔλFW ∼ 35 nm and ΔλP ∼ 30 nm at the applied voltage of 2 kV. The extinction spectra of alloy nanoparticle films show only one plasmon absorption it is concluded that mixing of gold and silver precursors leads to a homogeneous formation of alloy nanoparticles. The maximum of the SPR band tuned continuously from λmax ∼ 414–525 nm with increasing gold content. The SEM observations show the variable size and spherical structure of nanoparticle films.

In situ electric properties of Ag films deposited on rough substrates

Silver (Ag) films have been deposited on rough substrates (including frosted glass and silicone grease), and for comparison on flat glass, by DC-magnetron sputtering, and their sheet resistances measured in situ during deposition. It is found that the growth of Ag films proceeds through three distinct stages: discontinuous, semi-continuous, and continuous regimes. The sheet resistance on rough substrates jumps in the vicinity of the percolation threshold, whereas the resistance on flat substrates decreases monotonically during deposition. The abnormal in situ electric properties on rough substrates are well explained based on the differences of the growth mechanism and microstructure of Ag films on different substrates.

Influence of deposition temperature and pressure on microstructure and tribological properties of arc ion plated Ag films

The films deposited at low temperature (LT-films) have increasingly attracted theoretical and technical interests since such films exhibit obvious difference in structure and performances compared to those deposited at room temperature. Studies on the tribological properties of LT-films are rarely reported in available literatures. In this paper, the structure, morphology and tribological properties of Ag films, deposited at LT (166 K) under various Ar pressures on AISI 440C steel substrates by arc ion plating (AIP), are studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and a vacuum ball-on-disk tribometer, and compared with the Ag films deposited at RT (300 K). XRD results show that (200) preferred orientation of the films is promoted at LT and low Ar pressure. The Crystallite sizes are 70 nm–80 nm for LT-Ag films deposited at 0.2 Pa and 0.8 Pa and larger than 100 nm for LT-Ag films deposited at 0.4 Pa and 0.6 Pa, while they are 55 nm–60 nm for RT-Ag films deposited at 0.2 Pa–0.6 Pa and 37 nm for RT-Ag films deposited at 0.8 Pa. The surfaces of LT-Ag films are fibre-like at 0.6 Pa and 0.8 Pa, terrace-like at 0.4 Pa, and sphere-like at 0.2 Pa, while the surfaces of RT-Ag films are composed of sphere-like grains separated by voids. Wear tests reveal that, due to the compact microstructure LT-Ag films have better wear resistances than RT-Ag film. These results indicate that the microstructure and wear resistance of Ag films deposited by AIP can be improved by low temperature deposition.

Effect of Thicknesses on the Optical and Electrical Properties of Ag Films on PET Substrates

A series of Ag films with different thicknesses were prepared on polyethylene terephthalate (PET) substrates under identical conditions by thermal evaporation. The effect of the thickness on the optical and electrical properties of the films was studied. The morphology of the samples was investigated by atomic force microscopy (AFM). The optical and electrical properties were measured by spectrophotometer and four-point probe method, respectively. The experimental results show that the reflectance increases, while transmittance and resistivity decrease with the increase of the thickness. There exists a critical thickness of the film and it is 75 nm in this experiment. The optical and electrical properties of Ag films on PET substrates with thickness larger than critical thickness, are close to those of the conventional bulk silver. The resistivity of the 150-nm film is 3.0±0.2 μΩ•cm, which is lower than that of the 250-nm Ag film grown on BK-7 glass substrates.

Thermally stable very thin Ag films for electrodes

Low-resistivity metals such as Cu and Ag have been investigated for substitution of Al alloy films in the electrodes of thin film transistor used in active matrix liquid crystal displays. Though Ag has the drawback of agglomerating easily during heat treatment, improved thermal stability by modification of the Ag film into an Al∕Ag∕Al structure has been confirmed. In this paper, the surface morphology and electrical resistivity of this structure with various Ag layer thicknesses (from 95to50nm) are investigated. The Al∕Ag∕Al structure showed excellent stability after annealing at 600°C in vacuum, even with reduced thickness. The resistivity of the Al∕Ag(95nm)∕Al film and of the Al∕Ag(50nm)∕Al film after annealing were 1.8 and 2.4μΩcm, respectively. For comparison, properties of Ag films with the same thickness were investigated, but these films became discontinuous after annealing due to agglomeration. Modified Ag films maintained excellent properties after annealing, even when the Ag layer thickness was reduced.

Ag Films Deposited by Ionized Cluster Beam Deposition

ABSTRACTIonized cluster beam deposition (ICBD) technique has been used to deposit Ag films on both Si(111) and Si(100) substrates. Sizes of clusters in ionized cluster beam are found to distribute in a range of 100–600 atoms/cluster. X-ray diffraction (XRD), and α-step profile methods are used to analyze the properties of Ag films. As a comparison, Ag films deposited by conventional evaporation are also investigated. Highly textured Ag films with strong (111) orientation on Si (111) have been obtained at high accelerating voltage Va=4kV. The crystallinity and surface flatness of Ag films can be improved by ICBD at high accelerating voltages.

Tribological Improvement of Ag Films by Ion Beam Enhanced Deposition

This paper investigates the tribological properties of Ag film fabricated by ion enhanced deposition at atmospheric room temperature, whereby 150 keV Ar ion bombardment and Ag ion plating are performed simultaneously. In the absence of a lubricant, friction test apparatus employing ball-plate geometry is used. Also, properties such as film crystallinity, morphology and concentration profile are examined to study the high energy ion bombardment effect related to the film’s tribological properties. The activation of the mutual diffusion process which results from simultaneous ion bombardment during ion plating, as well as promotion of the crystallization in the ion bombarded film due to subsequent annealing, can greatly extend the mixing layer, and thus enhances the sliding life of the Ag film.