共查询到20条相似文献,搜索用时 11 毫秒
1.
Deok-kee Kim 《Thin solid films》2012,520(21):6571-6575
Hillock formation in Al thin films with varying thicknesses of SiO2 as a passivation layer was investigated during thermal cycling. Based on the stress measurements and the number of hillocks, 250 nm thick SiO2 was thick enough to suppress the hillock formation and the suppression of hillock at 250 nm passivation and the lack of suppression at thinner passivation is related to the presence/absence of protection against the diffusive flow of atoms from the surrounding area to the surface due to the biaxial compressive stresses present in the film through the weak spots in the passivation layer. The stress state of Al films measured during annealing (the driving force for hillock formation) did not vary much with SiO2 thickness. A small number of hillocks formed during the plasma enhanced chemical vapor deposition of SiO2 overlayers at 300 °C. 相似文献
2.
Tse-Chang Li Ming Tsung Kao Jen Fin Lin 《Journal of Materials Science: Materials in Electronics》2014,25(10):4425-4433
Al/glass specimens are prepared following the orthogonal table of five-level six-factorial (L25(56)) design. The governing factors for the preparation of the specimens are deposition conditions, annealing temperature and annealing time. Defects, including hillocks and nanovoids, are found to be created during the annealing process. The threshold value of the annealing stress (σ an ) required for the incipience of hillocks is thus determined. The stress change parameter, σ f –σ an (σ f :internal stress after annealing), is a positive value that increases linearly with σ an . The density of hillocks increases linearly with (σ f –σ an ) when the value of the stress change parameter is beyond the critical value (130 MPa). Nanovoids are produced even in specimens without hillocks. The wedge angle that forms in a specimen after wet etching linearly decreases with decreasing (σ f –σ an ). A high wedge angle lowers the hillock density at the wedge slope. The electrical resistance of the gate layer linearly increases with increasing product value (R*) of the mean size (area) and the density of nanovoids. R* increases nonlinearly with increasing (σ f –σ an ). 相似文献
3.
Mn1.85Co0.3Ni0.85O4 (MCN) thin films were prepared on Al2O3 substrates by chemical solution deposition method at different annealing temperature (650, 700, 750 and 800 °C). Effects of annealing temperature on microstructure and electrical properties of MCN thin films were investigated. The MCN thin film annealed at 750 °C is of good crystallization and compact surface. It shows lower resistance (4.8 MΩ) and higher sensitivity (3720.6 K) than those of other prepared films. It also has small aging coefficient (3.7%) after aging at 150 °C for 360 h. The advantages of good properties make MCN thin film very promising for integrated devices. 相似文献
4.
Xiaoyong Gao Mengke ZhaoZengyuan Zhang Chao ChenJiaomin Ma Jingxiao Lu 《Thin solid films》2011,519(19):6620-6623
Single-phased and (111)-oriented Ag2O film deposited using direct-current reactive magnetron sputtering is annealed using different annealing temperatures (Ta) for 1 h in Ar and H2 mixture. After hydrogen annealing, a very weak but clear Ag(200) diffraction peak begins to appear, and the Ag2O diffraction peak weakens at Ta = 175 °C. However, the Ag diffraction peak becomes discernable at Ta = 190 °C. No Ag2O diffraction peaks but rather Ag diffraction peaks are discerned at Ta = 200 °C. The hydrogen reduction effect can reduce the film's critical thermal decomposition temperature to 175 °C. After hydrogen annealing, the surface of the film evolutes from compact and uniform to osteoporosis, and then to a porous structure. Moreover, the optical properties of the film obviously change at Ta over 190 °C, indicating that the hydrogen reduction can significantly enhance the decomposition of Ag2O due to H2 dissociation on the surface followed by gaseous H2O molecule formation and desorption. 相似文献
5.
A TiO2 film was synthesized via a surfactant assisted sol-gel process and dip-coated on the surface of an open-celled aluminum foam. The film shows a typical mesoporous structure composed of anatase crystalline grains with the average size of 10 nm, and has the thickness of about 3.5 μm as well as the BET surface area of 78.1 m2/g. It exhibits high photocatalytic efficiency toward the decomposition of formaldehyde at continuous flow mode. The relatively small grain size of TiO2 and relatively thick mesoporous structure, which is favorable for high photochemical activity and the mass transfer of the reactants, should be responsible for the properties. 相似文献
6.
In current research, the effects of different Zr and B contents on the structure and tensile properties of Al–20%Mg alloy have been investigated by using Al–15Zr and Al–8B master alloys. Optical and scanning electron microscopy (SEM) were utilized to study the microstructures and fracture surfaces. Microstructural analysis of the cast alloy showed dendrites of primary α-phase within the eutectic matrix which consists of β-Al3Mg2 intermetallic and α-solid solution. After tensile testing, the optimum amounts for both Zr and B were found to be 0.5 wt.%. Ultimate tensile strength (UTS) value of the unrefined alloy increased from 168 MPa to 243 MPa and 236 MPa by adding 0.5% Zr and 0.5%B, respectively. The main mechanism for UTS enhancement was found to be due to the refinement of grains and also altering large dendrites of Al(α)-phase to finer structure. The study of fracture faces revealed that B/Zr addition changes the mode of fracture from brittle to rather ductile. 相似文献
7.
The up-conversion film is being tried to increase the photoelectric conversion efficiency of the silicon solar cell. To improve the efficiency of the photoluminescence film, the effects of the annealing temperature were investigated on the structure and photoluminescence of the ZnO up-conversion film, which was prepared using the sol-gel method and the spin-coating technique. The results show that the organic compounds and water in the ZnO film were completely eliminated when the annealing temperature reached 500?°C. The crystallinity of film is improved and the average grain size continuously increases as increasing the annealing temperature. The transmittance in the wavelength range of 400–2000?nm continuously increases as the annealing temperature increases from 500?°C to 700?°C, whilst it decreases first and then increases as the annealing temperature increases from 800?°C to 1000?°C. When the film is excited with a laser of 980?nm, there are two intense emission bands in the up-conversion emission spectra, 542-nm green light and 660-nm red light, corresponding to Ho3+: 5S2/5F4?→?5I8?and 5F5?→?5I8 transitions, respectively. In addition, the intensity of up-conversion luminescence for the film increases first and then decreases with the increase of the annealing temperature. When the annealing temperature is at 900?°C, the film consists of small round compact particles with a high degree of crystallization, reaching maximum up-conversion intensity of the film. 相似文献
8.
The results of mechanical testing on ultra-fine grained aluminum processed by accumulative roll-bonding (ARB) were analyzed with TEM observation and in accordance of the microstructural evolution upon annealing. It was found that rapid grain growth, with the corresponding decrease in strength, did not occur until the annealing temperature of 200 °C or higher. The oxide rolled into the material near the bonding interfaces was seen to act as an obstruction for grain boundary migration across said interfaces. More interestingly, the strain near the interface due to the surface preparation technique used during ARB was found to form discontinuous segregates consisting of smaller grains formed during annealing or even ARB processing of higher number of cycles. Such phenomenon is attributed to recovery or polygonization due to the strain incurred. This study has also demonstrated that yield point phenomenon may be observed in a commercially pure fcc metal when the grain size is within a certain range. 相似文献
9.
Effects of deposition conditions on physical properties and stresses of Pt and (Al, Si)Ox thin films
Jae-Suk Lee Jong-Wan Park Joon-Shik Park Hyo-Derk Park Sang-Mo Shin 《Journal of Materials Science Letters》1997,16(11):941-945
Abstracts are not published in this journal 相似文献
10.
Effects of deposition conditions on physical properties and stresses of Pt and (Al, Si)Ox thin films
Jae-Suk Lee Jong-Wan Park Joon-Shik Park Hyo-Derk Park Sang-Mo Shin 《Journal of Materials Science Letters》1998,16(11):941-945
Abstracts are not published in this journal
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
11.
The effects of Sr modification and aging treatment on the impact toughness of a near eutectic Al–11%Si–2.7%Cu–0.3%Mg–0.45%Fe alloy were investigated. Charpy impact tests were performed on unnotched specimens in the as-cast and heat-treated conditions. It was found that the presence of Fe- and Cu-containing phases increases the alloy brittleness which reduces impact toughness. The eutectic Si phase also plays an important role, where the size/morphology of the Si particles controls the area of α-Al matrix available which affects ductility and toughness. Increasing the Mn content leads to an increase in the volume fraction of the α-Al15(Mn,Fe)3Si2 phase formed and to sludge formation, which facilitates crack initiation and propagation. Crack propagation occurs mainly via the Al2Cu and/or α-Al15(Fe,Mn)3Si2 phases. In the non-modified alloys, the Si phase also plays a considerable role in the fracture process. The impact behaviour of aged alloys is influenced by the amount, size and morphology of hardening precipitates formed in the alloy, depending on the aging conditions. Aging at 240 °C produces a significant increase in the impact energy values of the low Mn-content alloys, as a result of alloy softening. The high Mn-content alloys also show a similar increase in impact energy values, but at a steady level across the same range of aging times, due to the persistence of the α-Al15(Mn,Fe)3Si2 phase. 相似文献
12.
Shanhu Bao 《Vacuum》2008,83(3):486-489
We are developing switchable mirror thin films based on an Mg-Ni alloy which can be switched between mirror and transparent states. The Mg4Ni alloy thin film was prepared on a glass substrate by DC magnetron co-sputtering of Mg and Ni targets and was subsequently covered in situ with a thin layer of Pd. The interface structure between Pd and Mg-Ni layers was found to have a crucial effect on the switching response and durability. By controlling the sputtering sequence and tailoring the interface structure, the switching response can be improved by 50-80% for the dehydrogenation process. The switching durability of the improved thin film is twice as long as that of a typical sample. We have also found that the switching response is dependent on the substrate temperature during sputtering. The dehydrogenation rate can be increased when the substrate is retained below room temperature. 相似文献
13.
K. L. Muratikov A. L. Glazov V. I. Nikolaev D. N. Rose D. E. Dumar 《Technical Physics Letters》2001,27(6):500-503
The Vickers indentation zones in Al2O3-SiC-TiC ceramics were studied by scanning laser photo-deflection and photoacoustic microscopy. The method of photoacoustic microscopy with piezoelectric detector (PAMPD) is sensitive to the internal stress distribution in the material. The effect of annealing on the PAMPD signal of the Al2O3-SiC-TiC ceramics was studied. An increase in the annealing time is accompanied by decrease in the PAMPD response from the vertices of radial cracks. 相似文献
14.
We presented a simple and efficient strategy for deposition of gold nanoparticles (AuNPs) upon transparent bare and indium tin oxide (ITO) film coated glass substrate using gold colloids as Au sources. The method involved two steps: embedding in polyvinyl alcohol (PVA) film and annealing at high temperature. The AuNPs deposited on solid substrate because of migration and coalescence of gold at high temperature. The optical and structural properties of the AuNPs were characterised by UV-vis absorption spectra and scanning electron microscopy. The results indicate that the surface of AuNPs upon substrate was clean as annealing at 600?°C for 0.5?h. The size of AuNPs deposited on ITO glass increased with annealing time and volume of PVA-AuNPs. Meanwhile, the localised surface plasmon resonance peak of AuNPs deposited on substrate was also gradual red-shift. In addition, the size of AuNPs deposited on ITO substrate was larger than that on bare glass. This work provides a simple, low-cost and large-scale method for fabrication of substrate-based AuNPs, which is benefit for exploiting biosensors, photonic devices and optoelectronic devices. 相似文献
15.
K. Vassilevski K. Zekentes K. Tsagaraki G. Constantinidis I. Nikitina 《Materials Science and Engineering: B》2001,80(1-3):370-373
Ohmic contacts to the top p-type layers of 4H-SiC p+–n–n+ epitaxial structures having an acceptor concentration lower than 1×1019 cm−3 were fabricated by the rapid thermal anneal of multilayer Al/Ti/Pt/Ni metal composition. The rapid thermal anneal of multilayer A1/Ti/Pt/Ni metal composition led to the formation of duplex cermet composition containing Ni2Si and TiC phases. The decomposition of the SiC under the contact was found to be down to a depth of about 100 nm. The contacts exhibited a contact resistivity Rc of 9×10−5 Ω cm−2 at 21°C, decreasing to 3.1×10−5 Ω cm−2 at 186°C. It was found that thermionic emission through the barrier having a height of 0.097 eV is the predominant current transport mechanism in the fabricated contacts. 相似文献
16.
Comparison of stress migration and electromigration in the fabrication of thin Al wires 总被引:1,自引:0,他引:1
A comparison between stress migration (SM) and electromigration (EM) in the fabrication of thin Al wires was made. The samples used in each case had the same structure and were manufactured by depositing a thin Al film on a SiO2 layer, a native oxide layer covering the Al film. Al microwires were formed by SM by wide-area atomic migration, meanwhile, nanowires were formed by EM through local accumulation of atoms. It was found that the mechanisms of wire formation were same in both SM and EM tests except the ability of accumulating atoms. Al micro/nanowires with controlled geometry can be fabricated by SM or EM. 相似文献
17.
Mo, Al2O3 single layer, Mo-Al2O3 granular cermet layer, Mo/Al2O3 tandem and an optimized Mo-Al2O3 multilayer coating with a double cermet layer configuration were deposited on stainless steel substrates by magnetron sputtering technique. The samples were annealed in vacuum at different temperatures ranging from 350 °C to 1000 °C for 2-5 h to evaluate their thermal stability. The spectral absorbance and thermal emissivity for the multi-layer selective coatings in the region of 1.3-25 μm were 0.91-0.93 and 0.19-0.27, respectively, depending on heat treatment temperature. Increasing annealing temperature has more obvious influence on the rise of emissivity than the drop of spectral absorbance. The microstructure, surface morphology, composition distribution and diffusion for various films before and after high temperature aging were investigated employing scanning electronic microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Fe2O3, as a diffusion barrier between Mo layer and SS substrate, effectively holds back the presence of Mo2C and Fe2MoC complex phases. Al2O3 is a stable phase even at 1000 °C for 3 h. However, defects such as widened boundaries, cracks and holes, which could appear in Al2O3 layer when heated at higher temperature than 650 °C, will provide the paths of Mo diffusion. Two diffusion modes of Mo, including inner self-congregation of Mo inside the cermet layer and Mo infiltration through the Al2O3 layer in Mo/Al2O3 tandem at 800 °C for 5 h, were observed after annealing. 相似文献
18.
Ayyaswamy VenkattramanAlina A. Alexeenko 《Vacuum》2012,86(11):1748-1758
Thin films of metal for electronics, nano/microelectromechanical systems and optical coatings are often prepared by various vacuum deposition techniques. Modeling such metal vapor flows using methods such as the direct simulation Monte Carlo (DSMC) can aid in the design and analysis of deposition systems and accelerate development of films with desired properties. The determination of suitable variable hard sphere (VHS) molecular model parameters for DSMC simulations using measured growth rate distribution is demonstrated with aluminum vapor as an example. Axisymmetric DSMC simulations using a VHS model corresponding to a reference diameter of 0.8 nm and a viscosity-temperature exponent of 1 are shown to agree well with available experimental data. The model is then used in two-dimensional DSMC simulations to study the interaction of plumes from multiple sources. An expression for substrate mass flux assuming no interaction between sources agrees well with DSMC simulations for a mass flow rate of 0.1 g/min corresponding to a Knudsen number (Kn) of about 0.1. The non-additive interaction of plumes at a higher flow rate of 1 g/min corresponding to a Kn of about 0.01 results in a higher mass flux non-uniformity in the DSMC simulations which is not captured by the simplified analytical expression. 相似文献
19.
Au layers with thickness of about 110 nm were sputter-deposited on unheated glass substrates coated with a Cr layer about 20 nm thick. The chamber was evacuated to a pressure of 2 Pa and then sputtering was carried out at Ar pressure of 4 Pa. The Au/Cr bilayer films were annealed in a vacuum of 5×10−4 Pa at 170°C, 180°C, 200°C and 250°C for from 5 to 120 min, respectively. Atomic force microscopy was used to observe the structural characteristic of the bilayer films. Auger electron spectroscopy was used to analyze the composition inside the Au layers. The sheet resistance of the films was measured using the four-point probe technique. The grain size of the bilayer film gradually increases with an increase in annealing temperature while its average surface roughness ranging from 4.5 to 6.8 nm does not show any systematic change with annealing temperature and time. No impurities such as carbon, nitrogen and oxygen are detected inside all of the Au layers. When the annealing temperature reaches 200°C and the annealing time exceeds 30 min, chromium atoms markedly diffuse into the Au layer. Furthermore, for the bilayer films annealed at 250°C, chromium atoms have markedly diffused into the Au layer even for annealing time of 5 min. Regardless of the increase in grain size of the Au layer, the diffusion of chromium atoms into the Au layer causes an increase in the resistivity of the bilayer film. 相似文献
20.
Thick aluminum-doped zinc oxide films were deposited at substrate temperatures from 100 °C to room temperature on polyethylene terephthalate by radio frequency magnetron sputtering, varying the deposition parameters such as radio frequency power and working pressure.Structural, optical and electrical properties were analyzed using an x-ray diffractometer, a spectrophotometer and a four-point probe, respectively. Films were polycrystalline showing a strong preferred c-axis orientation (002). The best optical and electrical results were achieved using a substrate temperature of 100 °C. Furthermore, high transmittances close to 80% in the visible wavelength range were obtained for those films deposited at the lowest Argon pressure used of 0.2 Pa. In addition, resistivities as low as 1.1 × 10− 3 Ω cm were reached deposited at a RF power of 75 W. Finally, a comparison of the properties of the films deposited on polymer and glass substrates was performed, obtaining values of the figure of merit for the films on polymer comparable to those obtained on glass substrates, 17,700 Ω− 1 cm− 1 vs 14,900 Ω− 1 cm− 1, respectively. 相似文献