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1.
Mechanical properties of thin films on substrates can be evaluated directly through nanoindentation. For a comprehensive study,
thin films should be characterized via Young’s modulus, yield stress and strain-hardening exponent at constant temperature.
In this paper, we evaluate these effects of thin films on silicon substrate through finite element analysis. Thin films, from
soft to hard relative to the silicon substrate, are investigated in three categories: soft films on hard substrates, soft
to hard films on no elastic mismatch substrates, and hard films on soft substrates. In addition to examining the load-displacement
curve, the normalized hardness versus normalized indentation depth is checked as well to characterize its substrate effect.
We found that the intrinsic film hardness can be acquired with indentation depths of less than 12% and 20% of their film thickness
for soft films on hard substrates and for soft to hard films on no elastic mismatch substrates, respectively. Nevertheless,
nanoindentation of hard films on soft substrates cannot determine the intrinsic film hardness due to the fact that a soft
substrate cannot support a hard film. By examining the von Mises stresses, we discovered a significant bending phenomenon
in the hard film on the soft substrate.
PACS 61.43.Bn; 62.20.-x; 68.03.Hj; 68.05.Cf; 68.08.De 相似文献
2.
《Current Applied Physics》2002,2(6):525-531
By regarding the tip blunting as a ball indentation at very low depth range (within about 80 nm in our experiments), the flow properties of Au thin films were derived from the indentation load–depth curve obtained by nanoindentation technique. The effects of pile-up or sink-in were considered in determining the real contact between the indenter and the specimen. The representative strain in indentation was defined in various ways and examined by comparing the flow properties derived from indentation load–depth curve with those measured by tensile test. The best definition was found to be the shear strain at contact edge multiplied by 0.1. When we considered the effects of pile-up or sink-in, the representative stress in indentation could also be determined, and was found to be one third of the mean contact pressure for fully plastic regime. As a more intrinsic property than hardness, the yield strengths of Au films with thickness of 0.56 and 0.99 μm were extrapolated from the derived true stress–true strain curve as 261±30 and 154±18 MPa, respectively. 相似文献
3.
Lead zirconate titanate (PZT) thin films are deposited on platinized silicon substrate by sol-gel process. The crystal structure and surface morphology of PZT thin films are characterized by X-ray diffraction and atomic force microscopy. Depth-sensing nanoindentation system is used to measure mechanical characteristics of PZT thin films. X-ray diffraction analyses confirm the single-phase perovskite structures of all PZT thin films. Nanoindentation measurements reveal that the indentation modulus and hardness of PZT thin films are related with the grain size and crystalline orientation. The increases of the indentation modulus and hardness with grain size are observed, indicating the reverse Hall-Petch effect. Furthermore, the indentation modulus of (1 1 1)-oriented PZT thin film is higher than those of (1 0 0)- and random-oriented films. The consistency between experimental data and numerical results of the effective indentation moduli for fiber-textured PZT thin films using Voigt-Reuss-Hill model is obtained. 相似文献
4.
In the present work, the nanoindentation of aluminum thin film on silicon substrate is investigated by three-dimensional molecular dynamic (MD) simulation. The film/substrate system is modeled by taking Lennard-Jones (LJ) potential to describe the interaction at the film-substrate interface. Different loading rate from 50 to 250 m/s is carried out in the simulation. The results showed that the hardness of the film increased with the loading rate. In order to study the effect of substrate on the mechanical properties of thin film, nanoindentation process on monolithic Al material is also simulated. The simulation results revealed that indentation pile-up in the aluminum film is significantly enhanced by the substrate. The substrate also affects the loading force during the nanoindentation. At the beginning of the indentation, the loading force is not affected by the substrate. Then, it is getting smaller caused by the interface. As the film is penetrated, the loading force increased rapidly caused by the hard substrate. These results were coincident with the previous reported experiments. 相似文献
5.
Quan Wang Ran Hu Jianning Ding Liyun Jiang 《Applied Physics A: Materials Science & Processing》2011,105(1):153-159
Thin films of hydrogenated silicon were deposited on glass and single-crystalline silicon substrates using a capacitively
coupled radio-frequency plasma-enhanced vapor-deposition system with the help of direct-current bias stimulation. Micro-Raman
scattering was applied to investigate the microstructure of the thin films obtained. The crystalline volume fraction, X
c, was obtained from the Raman spectra. Microscopic mechanical characterization of the thin films was carried out by nanoindentation
based on the conventional depth-sensing indentation method. An analytical relation between X
c and the elastic modulus was thereby established. The elastic modulus of the film on a glass substrate was found to be lower
than that of the film on a monocrystalline silicon substrate with the same X
c. The grain size of a phosphorus-doped thin film was smaller than that of the intrinsic one, with greater ordering of the
grains and X
c was found to be usually above 40%. A film with boron doping was on the opposite side, with X
c usually below 40%. In the phosphorus-doped, intrinsic, and boron-doped films, the elastic moduli were lower when the X
c values were 45%, 30%, and 15%, respectively. 相似文献
6.
D.G. Gromov A.I. Mochalov V.P. Pugachevich E.P. Kirilenko A.Y. Trifonov 《Applied Physics A: Materials Science & Processing》1997,64(5):517-521
73 Co27 and Ti73Co27- N during thermal annealing has been studied by SIMS, AES and XRD methods. It has been shown that in case of Ti73Co27 the CoSi2 layer was not formed and the formation of ternary silicide compounds CoTiSi and Co3Ti2Si took place. At the same time in case of Ti73Co27- N the bottom layer CoSi2 and the upper layer based on TiN were formed. The interaction behaviour has been found to depend on nitrogen concentration
in initial film. For high amount of nitrogen the diffusion of Si atoms into upper layer and Si3N4 phase formation were observed. The possible variants of solid-phase interaction between silicon and the alloys containing
intermetallic compounds and influence of nitrogen on this process are discussed.
Received: 25 September 1996 / Accepted: 11 October 1996 相似文献
7.
A. Matoussi F. Ben Nasr R. Salh S. Guermazi H.-J. Fitting 《Journal of luminescence》2010,130(3):399-403
GaN films have been grown on porous silicon at high temperatures (800-1050 °C) by metal organic vapor phase epitaxy. The optical properties of GaN layers were investigated by photoluminescence (PL) and cathodoluminescence (CL) spectroscopy. PL spectra recorded at 5 K exhibit excitonic emissions around 3.36-3.501 eV and a broad yellow luminescence at 2.2 eV. CL analysis at different electron excitation conditions shows spatial non-uniformity in-depth of the yellow and the band-edge emissions. These bands of luminescence are broadened and red- or blue-shifted as the electron beam penetrates in the sample. These behaviors are explained by a change of the fundamental band gap due to residual strain and the local thermal effect. It was found that the use of AlN buffer layer improves the crystalline quality and the luminescence property of GaN. 相似文献
8.
Thin silicon oxynitride films with excellent uniformity were prepared by plasma enhanced CVD. Oxygen incorporation leads to improved breakdown behavior and to reduction of the film conductivity compared to PECVD silicon nitride layers. Thin PECVD silicon oxynitride films deposited on single crystal and poly-Si exhibit good insulation properties in both cases. 相似文献
9.
10.
R. Kuschnereit H. Fath A. A. Kolomenskii M. Szabadi P. Hess 《Applied Physics A: Materials Science & Processing》1995,61(3):269-276
Mechanical and elastic properties of a-SiH films were measured by broadband Surface Acoustic Wave Spectroscopy (SAWS). In the frequency range achieved, the SAW dispersion curves extend to 300 MHz, which allowed the density, Young's modulus, and Poisson's ratio to be evaluated for films grown by laser CVD or plasma CVD with different hydrogen concentrations. The films deposited by either method have the best mechanical and elastic properties. at a hydrogen concentration of about 10 at. %. For this material, a density of (2300±20) kg/m3 and Young's modulus of (134±5) GPa was determined. The network structures of amorphous silicon are discussed by applying the constraint-counting model to estimate the mean coordination number. 相似文献
11.
Cathodoluminescence (CL) spectra for the Si nanocrystallites embedded in a matrix of silicon oxide films are measured at room temperature. The CL spectra consist of two principal bands whose peak energies are in a near-infrared (NIR) region (<1.6 eV) and in a blue region (2.6 eV), respectively. The spectral feature of the NIR CL band is similar to the corresponding PL spectra. The strong correlation between the presence of Si nanocrystallites and the formation of the NIR CL band are found as well as the PL spectrum. The peak energy of the blue CL band is slightly lower than that of the luminescence band originating from oxygen vacancies (≡Si–Si≡) in SiO2. Therefore, the blue CL band is considered to come from Sin clusters with n3 in the oxide matrix. Under irradiation of electron beams, degradation of the intensity is observed for both the CL bands but the decay characteristics are different. 相似文献
12.
采用甚高频等离子体增强化学气相沉积(VHF-PECVD)技术制备了不同腔室环境下的微晶硅薄膜.对单室沉积掺杂层p材料后遗留在腔室中的硼对本征微晶i材料电学特性和结构特性的影响进行了详细研究.测试结果表明:单室沉积p层后的硼降低了微晶i层材料的暗电导,增加了材料的光敏性;由于硼对i层污染程度的不同,使得材料的激活能发生了变化;腔室中残余的硼也导致微晶硅薄膜的结晶状况恶化,同时弱化了材料的(220)择优取向.而在较高功率和较强氢稀释下制备的晶化率较高,(220)晶向明显择优的材料受硼污染影响相对减小.
关键词:
单室
甚高频等离子体增强化学气相沉积
微晶硅
硼 相似文献
13.
Chuan C. Chang G. Quintana 《Journal of Electron Spectroscopy and Related Phenomena》1973,2(3):363-376
Silicon out-diffusion through ? 3000 Å tungsten films deposited on silicon by r.f. sputtering was studied using Auger spectroscopy. Silicon first diffuses to the tungsten film surface by grain boundary diffusion and surface migration. The out-diffusion kinetics were most strongly dependent on the thickness of the silicon dioxide layer between tungsten and silicon, and this (native) oxide thickness varied with substrate doping. The out-diffusion rate was independent of tungsten film thickness at 540 Å and 2400 Å. For substrates from which the native oxide was removed by backsputtering just prior to tungsten deposition, no Si out-diffusion to the W film surface was observed until almost the entire film had converted to WSi2. 相似文献
14.
Mechanical properties of Al/a-C nanocomposite thin films synthesized using a plasma focus device
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Z.A.Umar R.S.Rawat R.Ahmad A.K.Kumar Y.Wang T.Hussain Z.Chen L.Shen Z.Zhang 《中国物理 B》2014,23(2):25204-025204
The Al/a-C nanocomposite thin films are synthesized on Si substrates using a dense plasma focus device with alu- minum fitted anode and operating with CH4/Ar admixture. X-ray diffractometer results confirm the formation of metallic crystalline Al phases using different numbers of focus shots. Raman analyses show the formation of D and G peaks for all thin film samples, confirming the presence of a-C in the nanocomposite thin films. The formation of Al/a-C nanocomposite thin films is further confirmed using X-ray photoelectron spectroscopy analysis. The scanning electron microscope results show that the deposited thin films consist of nanoparticles and their agglomerates. The sizes of th agglomerates increase with increasing numbers of focus deposition shots. The nanoindentation results show the variations in hardness and elastic modulus values of nanocomposite thin film with increasing the number of focus shots. Maximum values of hardness and elastic modulus of the composite thin film prepared using 20 focus shots are found to be about 10.7 GPa and 189.2 GPa, respectively. 相似文献
15.
The hardness and the elastic modulus of Cu thin films on Si, Ti, Cu, and Al substrates are investigated. It is demonstrated that the use of the Oliver-Pharr method in combination with the technique for evaluating the true hardness makes it possible to determine uniquely the hardness of Cu thin films at different ratios between the hardnesses of the film and the substrate. The elastic modulus of thin films can be correctly measured by the Oliver-Pharr method only in the case where the film and the substrate exhibit identical elastic properties. In order to determine the elastic moduli of films with the use of the parameter P/S 2, the film and the substrate should have close values of both the hardness and the elastic modulus. 相似文献
16.
17.
Effect of substrate temperature and pressure on properties of microcrystalline silicon films
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In this paper intrinsic microcrystalline silicon films have been prepared by very high
frequency plasma enhanced chemical vapour deposition (VHF-PECVD) with
different substrate temperature and pressure. The film properties were
investigated by using Raman spectra, x-ray diffraction, scanning
electron microscope (SEM), and optical
transmittance measurements, as well as dark conductivity. Raman results
indicate that increase of substrate temperature improves the microcrystallinity
of the film. The crystallinity is improved when the pressure increases from
50Pa to 80Pa and the structure transits from microcrystalline to amorphous
silicon for pressure higher than 80Pa. SEM reveals the effect of substrate
temperature and pressure on surface morphology. 相似文献
18.
Hong Cai Honglie Shen Linfeng Lu Zhengxia Tang 《Journal of Physics and Chemistry of Solids》2009,70(6):967-971
In the present work, ZnO was deposited on porous silicon substrates by sol-gel spin coating and rf magnetron sputtering. The porous silicon (PS) substrates were formed by electrochemical anodization on p-type (1 0 0) silicon wafer, and the starting material for ZnO was Zinc acetate dehydrate. Raman spectroscopy revealed the good quality of the porous silicon substrate. XRD analysis showed that highly (0 0 2) oriented ZnO thin films were formed. SEM, AFM and optical microscope have been used to understand the effects of the substrate on crystalline properties of the samples. The results indicated that the porous silicon substrate is beneficial to improve the crystalline quality in lattice mismatch heteroepitaxy due to its sponge-like structure. 相似文献
19.
N. Rehse C. Wang M. Hund M. Geoghegan R. Magerle G. Krausch 《The European physical journal. E, Soft matter》2001,4(1):69-76
We study the wetting behaviour of thin polystyrene (PS) films on regularly corrugated silicon substrates. Below a critical
film thickness the PS films are unstable and dewet the substrates. The dewetting process leads to the formation of nanoscopic
PS channels filling the grooves of the corrugated substrates. Films thicker than the critical thickness appear stable and
follow the underlying corrugation pattern. The critical thickness is found to scale with the radius of gyration of the unperturbed
polymer chains.
Received 6 April 2000 and Received in final form 24 August 2000 相似文献
20.
采用x射线小角散射(SAXS)技术研究了由射频等离子体增强化学气相沉积(rf-PECVD)、 热丝化学气相沉积(HWCVD)和等离子体助热丝化学气相沉积(PE-HWCVD)技术制备的微晶硅( μc-Si:H)薄膜的微结构.实验发现,在相同晶态比的情况下,PECVD沉积的μc-Si:H薄膜微 空洞体积比小,结构较致密,HWCVD沉积的μ-Si:H薄膜微空洞体积比大,结构较为疏松,PE -HWCVD沉积的μc-Si:H薄膜,由于等离子体的敲打作用,与HWCVD样品相比,微结构得到明 显改善.采用HWCVD二步法和PE-HWCVD加适量Ar离子分别沉积μc-Si:H薄膜,实验表明,微结 构参数得到了进一步改善.45°倾角的SAXS测量显示,不同方法制备的μc-Si:H薄膜中微空 洞分布都呈各向异性.红外光谱测量也证实了SAXS的结果.
关键词:
微晶硅薄膜
微结构
微空洞
x射线小角散射 相似文献