共查询到20条相似文献,搜索用时 15 毫秒
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残余应力是光学薄膜研究的一个重要组成部分,它对光学元器件有很大的影响。根据弹性力学原理,基于应变不匹配,提出了一种可以预测薄膜残余应力分配的理论模型计算方法,并将计算结果与干涉仪测量值进行了对比。利用所建立的模型分析了薄膜参数变化时基底残余应力的变化情况。结果表明:所建模型合理;随着镀膜温度的增加,基底总残余应力随镀膜温度升高而呈增大的趋势;本征应力变化不太大;随着基底厚度的减小,基底上下表面应力呈增大的趋势,而薄膜应力则呈减小趋势,但变化趋势很小。基底的中心轴约位于基底上表面以下2/3处。 相似文献
3.
用CVD两步法在常压下于p型Si(100)衬底上沉积出具有较好择优取向的多晶ZnO薄膜。在325nm波长的光激发下,室温下可观察到显著的紫外光发射(峰值波长381nm)。高温退火后氧空位缺陷浓度增加,出现了一个450~600nm的绿光发光带,发光峰值在510nm。作为比较,用一步法生长的ZnO薄膜结晶质量稍差。在其PL谱中不仅有峰值波长389nm的紫外发射而且还出现了一个很强的蓝光发光中心(峰值波长437nm),退火后同样产生绿光发光带。对这两种绿光发光带的发光机制进行了研究,认为前者源于VO,而后者与OZn有密切的关系。 相似文献
4.
Zinc oxide thin films have been deposited on glass substrates at a substrate temperature of 673 K by spray pyrolysis. The
samples are annealed in ambient atmosphere at various temperatures. The effect of annealing on structural, electrical, and
optical properties of ZnO films has been investigated. X-ray diffraction patterns show that crystallinity of the ZnO films
has been improved after annealing. The morphology of ZnO thin films is studied by atomic force microscopy. The tensile strain
(compressive stress) is found to decrease with increase in annealing temperature which indicates the relaxation of tensile
strain in ZnO thin films. A decrease in energy band gap is observed with increase of annealing temperature. The mechanism
of blue-green luminescence of ZnO thin film has been analyzed. The resistivity is found to decrease with annealing temperature. 相似文献
5.
Fe-N thin films were prepared by dc magnetron sputtering at elevated temperature of 80 °C. The residual stress of the thin film was characterized by means of grazing incidence X-ray diffraction method. The effect of magnetron sputtering parameter on residual stress was investigated. The results indicate that the nitrogen content in working gas has great effects on the residual stress in the Fe-N thin film, and the residual stress increases firstly and then decreases with the increasing of nitrogen content in working gas. Curie temperature measurement shows that tensile residual stress enhances the ferromagnetic-paramagnetic transition temperature of Fe-N thin films under the condition of same phase composition. 相似文献
6.
Ti added In-Zn-O thin films and their application to thin film transistors were studied. The In-Zn-O films were deposited by pulsed plasma deposition using targets with various Ti contents added. High content of Ti in In-Zn-O films was found to induce a decrease in carrier concentration. The effect was attributed to suppression of oxygen vacancies by Ti incorporation. For thin film transistors with Ti added In-Zn-O as channel layer materials, threshold voltage showed positive shift as Ti content increases and field effect mobility was not decreased at the same time. Results of a bias stress experiment on device fabricated at room temperature are also given. 相似文献
7.
Herminghaus S 《The European physical journal. E, Soft matter》2002,8(2):237-243
It is discussed how the proximity of a free surface or mobile interface may affect the strain relaxation behavior in a viscoelastic
material, such as a polymer melt. The eigenmodes of a viscoelastic film are thus derived, and applied in an attempt to explain
the experimentally observed substantial shift of the glass transition temperature of sufficiently thin polymer films with
respect to the bulk. Based on the idea that the polymer freezes due to memory effects in the material, and exploiting results
from mode-coupling theory, the experimental findings of several independent groups can be accounted for quantitatively, with
the elastic modulus at the glass transition temperature as the only fitting parameter. The model is finally applied discussing
the possibility of polymer surface melting. A surface molten layer is predicted to exist, with a thickness diverging as the
inverse of the reduced temperature. A simple model of thin polymer film freezing emerges which accounts for all features observed
experimentally so far.
Received 8 August 2001 相似文献
8.
The development of compressive strain in metal thin films grown at low temperature has recently been revealed via x-ray diffraction and explained by the assumption that a large number of vacancies were incorporated into the growing films. The results of our molecular dynamics and parallel temperature-accelerated dynamics simulations suggest that the experimentally observed strain arises from an increased nanoscale surface roughness caused by the suppression of thermally activated events at low temperature combined with the effects of shadowing due to off-normal deposition. 相似文献
9.
The surface roughness and residual stress development in Fe-N thin films prepared by compound technology—combining magnetron sputtering with plasma based ion implantation were investigated by means of atomic force microscope and synchrotron radiation. The results indicate that the grain size of the thin film increases with the increasing of nitrogen ion implantation time, and the state of residual stress is related closely to the formation mechanism of thin films. With the nitrogen ion implantation time increasing, the residual stress of the thin film changes into tensile stress from initial compressive stress, and the tensile stress decreases with the further increasing of ion implantation time. 相似文献
10.
采用溶胶-凝胶(sol-gel)工艺在Pt/TiO2/SiO2/p-Si(100)衬底上制备出Bi4Ti3O12(BIT)和Bi3.25La0.75Ti2.97V0.03O12(BLTV)铁电薄膜,研究了La,V共掺杂对BIT薄膜的晶体结构和电学性能的影响.BIT薄膜为c轴择优取向,BLTV薄膜为随机取向,拉曼光谱分析表明V掺杂降低了TiO6(或VO6)八面体的对称性,也增强了Ti—O键(或V—O键)杂化.BLTV薄膜的剩余极化Pr为25.4μC/cm2,远大于BIT薄膜的9.2μC/cm2,表现出良好的铁电性能.疲劳、漏电流测试显示BLTV薄膜具有优良的抗疲劳特性和漏电流特性,表明La,V共掺杂能有效地降低薄膜中的氧空位. 相似文献
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Residual compressive stress and intensity of infrared absorption of cubic BN films prepared by plasma enhanced chemical vapor deposition 下载免费PDF全文
Theoretical and experimental investigations on the dependence of the intensity of infrared (IR) absorption of poly- crystalline cubic boron nitride thin films under the residual compressive stress conditions have been performed. Our results indicate that the intensity of the IR absorption is proportional to the total degree of freedom of all the ions in the ordered regions. The reduction of interstitial Ar atom concentration, which causes the increase in the ordered regions of cubic boron nitride (cBN) crystallites, could be one cause for the increase in the intensity of IR absorption after residual compressive stress relaxation. Theoretical derivation is in good agreement with the experimental results concerning the IR absorption intensity and the Ar interstitial atom concentration in cubic boron nitride films measured by energy dispersion X-ray spec- troscopy. Our results also suggest that the interstitial Ar is the origin of residual compressive stress accumulation in plasma enhanced cBN film deposition. 相似文献
13.
The Dewetting of thin polymer films (60–300 nm) on a
non-wettable liquid substrate has been studied in the vicinity of
their glass transition temperature. In our experiment, we observe a global
contraction of the film while its thickness remains uniform. We
show that, in this case, the strain corresponds to simple extension, and we verify that it is linear with the stress applied
by
the surface tension. This allows direct measurement of the
stress/strain response as a function of time, and thus permits the
measurement of an effective compliance of the thin films. It is,
however, difficult to obtain a complete viscoelastic
characterization, as the short time response is highly dependant on
the physical age of the sample. Experimental results underline the
effects of residual stress and friction when dewetting is analyzed
on rigid substrates. 相似文献
14.
Ngai KL 《The European physical journal. E, Soft matter》2002,8(2):225-235
Large increases of mobility of local segmental relaxation observed in polymer films as the film thickness is decreased, as
evidenced by decreases of the glass temperature, are not found for relaxation mechanisms that have longer length scales including
the Rouse relaxation modes and the diffusion of entire polymer chains. We show that the coupling model predictions, when extended
to consider polymer thin films, are consistent with a large increase of the mobility of the local segmental motions and the
lack of such a change for the Rouse modes and the diffusion of entire polymer chains. There are two effects that can reduce
the coupling parameter of the local segmental relaxation in thin films. One is the chain orientation that is induced parallel
to the surface when the film thickness h becomes smaller than the end-to-end distance of the chains and the other is a finite-size effect when h is no longer large compared to the cooperative length scale. Extremely thin ( ≈ 1.5 nm) films obtained by intercalating a
polymer into layered silicates have thickness significantly less than the cooperative length scale near the bulk polymer glass
transition temperature. As a result, the coupling parameter of the local segmental relaxation in such thin films is reduced
almost to zero. With this plausible assumption, we show the coupling model can explain quantitatively the large decrease of
the local segmental relaxation time found experimentally.
Received 1 August 2001 and Received in final form 1 December 2001 相似文献
15.
《Composite Interfaces》2013,20(3):221-231
Preferentially oriented (0 0 2) ZnO thin films with c-axis-oriented wurtzite structure have been grown on Si (1 0 0) and glass substrates using radio frequency magnetron sputtering. The residual stresses have been determined and calculated via the Stoney formalism. The ZnO thin films have been also characterised by X-ray diffraction and scanning electron microscope, and their stoichiometry was verified by Rutherford backscattering spectroscopy. The evolution of the residual stress was studied as a function of film thickness in the 10–1200 nm range. A growth scenario is proposed and a possible correlation between the residual stress, film’s texture and crystallographic orientation is highlighted. The crystalline quality was found to improve, while the stress values decreased with increasing thickness, and as a ramification the thicker films developed better sensing response to gases. The mechanical (stress) and electrical properties of the films were also investigated as a function of the film thickness, which tended to manifestly improve in dependence on thickness as well. We attribute this to the fact that the thinner films are under vehement misfit stress that declines with increasing the film thickness further. 相似文献
16.
K.B. Ruan H.W. Ho R.A. Khan P. Ren W.D. Song A.C.H. Huan L. Wang 《Solid State Communications》2010,150(43-44):2158-2161
Carbon-doped In2O3 thin films exhibiting ferromagnetism at room temperature were prepared on Si (100) substrates by the rf-magnetron co-sputtering technique. The effects of carbon concentration as well as oxygen atmosphere on the ferromagnetic property of the thin films were investigated. The saturated magnetizations of thin films varied from 1.23 to 4.86 emu/cm3 with different carbon concentrations. The ferromagnetic signal was found stronger in samples with higher oxygen vacancy concentrations. In addition, deposition temperature and different types of substrates also affect the ferromagnetic properties of carbon-doped In2O3 thin films. This may be related to the oxygen vacancies in the thin film system. The experiment suggests that oxygen vacancies play an important role in introducing ferromagnetism in thin films. 相似文献
17.
S. Besseghini A. Gambardella V. A. Chernenko M. Hagler C. Pohl P. Müllner M. Ohtsuka S. Doyle 《The European physical journal. Special topics》2008,158(1):179-185
A series of Ni51.4Mn28.3Ga20.3/Si(100) thin film composites with different film thicknesses varying from 0.1 to 5 μm have been prepared by magnetron sputtering
and subsequently annealed. X-ray powder diffraction patterns of the films show the features associated with the lattice-modulated
martensitic phase and/or cubic austenite at room temperature. 220-fiber texture was confirmed by the X-rays measurements made
at 150 °C. While the Curie temperature is almost film thickness independent, the martensitic transformation temperature shows
a strong descended dependence in the submicron range. The substrate curvature measurements demonstrate that the forward and
reverse martensitic transformation in the films is accompanied by the reversible relaxation and accumulation of residual stress,
originally created by the thermal treatment due to the difference in thermal expansion of the film and substrate. The values
of residual stresses measured by both substrate curvature and X-rays diffraction methods at constant temperatures are found
to be dependent on the film thickness. This behavior appears in correlation with the thickness dependence of the transformation
temperature. 相似文献
18.
由于铍薄膜极易被X射线穿透, 传统的几何模式下很难获得有效的X射线衍射应力分析结果. 本文采用掠入射侧倾法分析SiO2基底上Be薄膜残余应力, 相比其他衍射几何方法, 提高了衍射的信噪比, 获得的薄膜应力拟合曲线线形较好. 对Be薄膜的不同晶面分析, 残余应力结果相同, 表明其力学性质各向同性; 利用不同掠入射角下X射线的穿透深度不同, 获得应力在深度方向上的分布; 由薄膜面内不同方向的残余应力相同, 确定薄膜处于等双轴应力状态.
关键词:
Be薄膜
X射线衍射
应力 相似文献
19.
Ch.G. Wu W.L. Zhang Y.R. Li X.Zh. Liu J. Zhu B.W. Tao 《Infrared Physics & Technology》2006,48(3):187-191
Ba0.65Sr0.35TiO3 (BST) thin films were deposited by RF sputtering with a very thin Ba0.65Sr0.35RuO3 (BSR) seeding-layer on Pt/Ti/SiO2/Si substrate. The crystallization of BST thin films and the surface morphology of BSR seeding-layer were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. XRD patterns show that the BSR seeding-layer affected the orientation of BST thin film, which is highly a-axis textured. It was also found that the BSR seeding-layer had a marked influence on the dielectric properties of BST thin films. Comparing with BST thin films directly deposited on Pt electrode, the dielectric relaxation can be suppressed and dielectric constant increased due to a possible reduction of interface oxygen vacancies at BST/BSR interface. Moreover, J–V measurement indicates that the leakage current density of BST thin films on BSR seeding-layer were greatly reduced compared with that of BST thin films directly on Pt electrodes. The pyroelectric coefficient of BST thin films with BSR seeding-layer is 7.57 × 10−7 C cm−2 K−1 at 6 V/μm at room temperature (RT). Our results reveal that high pyroelectric property of BST thin film could be achievable using BSR seeding-layer as a special buffer. 相似文献
20.
Gebhardt U Kasper NV Vigliante A Wochner P Dosch H Razavi FS Habermeier HU 《Physical review letters》2007,98(9):096101
We present an extended synchrotron x-ray scattering study of the structure of thin manganite films grown on SrTiO3(001) substrates and reveal a new kind of misfit strain relaxation process which exploits twinning to adjust lattice mismatch. We show that this relaxation mechanism emerges in thin films as one-dimensional twinning waves which freeze out into a twin domain pattern as the manganite film continues to grow. A quantitative microscopic model which uses a matrix formalism is able to reproduce all x-ray features and provides a detailed insight into this novel relaxation mechanism. We further demonstrate how this twin angle pattern affects the transport properties in these functional films. 相似文献