共查询到20条相似文献,搜索用时 15 毫秒
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Cui-xia Liu Yan-qing Yang Rong-jun Zhang Xiao-xia Ren 《Computational Materials Science》2008,43(4):1036-1041
A three-dimensional atomic-scale kinetic Monte Carlo (KMC) model of {1 1 1}-oriented SiC film deposited by chemical vapor deposition is established in this paper. The growth process of {1 1 1}-oriented atomic-scale SiC film is simulated. The model includes two parts: the first is kinetic process of chemical reaction and the second is deposition and diffusion of substrate surface. In this model, the relationship between temperature and growth rate, surface roughness and relative density and the relationship between growth rate and surface roughness and relative density are studied. The result indicates that the growth of film has three stages including formation of little islets, mergence and expanding of islets and dynamic balance between islets. With increase of substrate temperature, deposition rate, surface roughness and height of film all increase. With increase of deposition rate, surface roughness increases while relative density decreases. 相似文献
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Summary Simulation strategies for chemical vapor deposition (CVD) of thin solid films are presented, with emphasis on direct simulation Monte Carlo methods for analyzing and predicting physical phenomena occurring at low pressures and in micron-sized substrate features. The Monte Carlo approach is placed in perspective, relative to standard continuum mechanics-based strategies for modeling of CVD systems. Design issues that may be addressed through the developed methods are exemplified with computations for a new, technologically important CVD process for epitaxy of Si and SixGe1-x alloys. Specifically, radiative heat transfer, rarefied gas-flow characteristics, species separation caused by pressure and thermal diffusion, growth-rate uniformity vs. surface reactivity, and deposition in microscopic features are addressed as parts of the overall CVD reactor-design approach. Process implications of rarefied transport effects unique to very low pressure CVD conditions are described. A new profile evolution technique is also introduced which predicts film topology, as well as the microstructure of the film. 相似文献
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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
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J. Flicstein S. Pata J. M. Le Solliec L. S. How Kee Chun J. F. Palmier J. L. Courant 《Computational Materials Science》1998,10(1-4):116-126
Microstructural changes of surfaces and bulk of a SiN: H were investigated at the atomic level by a simulator. The simulator is based on a solid-on-solid type model for ultraviolet localized-chemical vapor deposition. The calculations consider the well-defined photolysis products adsorbed at atomic sites. Incorporation of main species is enabled by a Monte Carlo-Metropolis simulation technique. Photodeposition rates are obtained using bond dissociation energies. In this manner, the dependence of root-mean-square deviation of surface roughness and bulk porosity on operating conditions can be predicted. Photonucleation and photodeposition with a UV low pressure mercury lamp at low pressure and temperature were simulated onto indium phosphide substrate. 相似文献
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Katsuyuki Okada 《Science and Technology of Advanced Materials》2013,14(7-8):624-634
Nanocrystalline diamond films have attracted considerable attention because they have a low coefficient of friction and a low electron emission threshold voltage. In this paper, the author reviews the plasma-enhanced chemical vapor deposition (PE-CVD) of nanocrystalline diamond and mainly focuses on the growth of nanocrystalline diamond by low-pressure PE-CVD. Nanocrystalline diamond particles of 200–700 nm diameter have been prepared in a 13.56 MHz low-pressure inductively coupled CH4/CO/H2 plasma. The bonding state of carbon atoms was investigated by ultraviolet-excited Raman spectroscopy. Electron energy loss spectroscopy identified sp2-bonded carbons around the 20–50 nm subgrains of nanocrystalline diamond particles. Plasma diagnostics using a Langmuir probe and the comparison with plasma simulation are also reviewed. The electron energy distribution functions are discussed by considering different inelastic interaction channels between electrons and heavy particles in a molecular CH4/H2 plasma. 相似文献
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Nanocrystalline diamond films have attracted considerable attention because they have a low coefficient of friction and a low electron emission threshold voltage. In this paper, the author reviews the plasma-enhanced chemical vapor deposition (PE-CVD) of nanocrystalline diamond and mainly focuses on the growth of nanocrystalline diamond by low-pressure PE-CVD. Nanocrystalline diamond particles of 200–700 nm diameter have been prepared in a 13.56 MHz low-pressure inductively coupled CH4/CO/H2 plasma. The bonding state of carbon atoms was investigated by ultraviolet-excited Raman spectroscopy. Electron energy loss spectroscopy identified sp2-bonded carbons around the 20–50 nm subgrains of nanocrystalline diamond particles. Plasma diagnostics using a Langmuir probe and the comparison with plasma simulation are also reviewed. The electron energy distribution functions are discussed by considering different inelastic interaction channels between electrons and heavy particles in a molecular CH4/H2 plasma. 相似文献
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采用直流热阴极PCVD(Plasma chemical vapor deposition)法间歇生长模式制备金刚石膜,通过加入周期性的刻蚀阶段清除金刚石膜在一定生长期中形成的石墨和非晶碳等杂质,实现了金刚石膜生长的质量调控。间歇式生长过程分为沉积阶段和刻蚀阶段,两个阶段交替进行。采用Raman光谱、SEM和XRD对所制金刚石膜的品质进行了表征,并与同样生长条件下连续生长模式制备的金刚石膜样品进行了比较。结果表明,当单个生长周期为30 min(沉积时间为20 min、刻蚀时间为10 min)时,直流热阴极PCVD法间歇生长模式制备的金刚石膜中的非金刚石相杂质含量低于连续间歇生长模式制备的金刚石膜。 相似文献
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研究了热丝化学气相沉积法(HFCVD)制备得到掺硼金刚石膜电极电催化氧化典型有机物苯酚的特性.Raman光谱测试显示制备BDD电极具有较好的金刚石相,循环伏安测试表明该电极具有较高的析氧过电位(+2.3V vsSCE).在电催化氧化苯酚过程中,化学需氧量(COD)能够有效去除,降解过程中有较高的电流效率,在COD较高的情况下,瞬时电流效率(ICE)可达100%,随着COD的降低ICE逐渐减少.催化实验结果表明,BDD电极是一种优良的电催化降解有机物新型电极. 相似文献
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Wook Hee Koh 《Vacuum》2009,84(5):550-553
Monte Carlo simulation techniques are used to study the dynamical properties of charged particles in point-to-plane corona discharge. The numerical model includes the release of electron-ion pairs by photoionization and secondary electron emission from cathode as well as the first Townsend ionization. The simulation results of negative corona discharge in nitrogen show that electron avalanche takes place in the region of high electric field near pin electrode and the photoionization is the essential mechanism to sustain the discharge as well as electron impact ionization. 相似文献
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Yasunobu Akiyama Katsuya Shitanaka Young-Sik Shin Nobuyuki Imaishi 《Thin solid films》2007,515(12):4975-4979
Lithium niobate films grown epitaxially on sapphire substrate were prepared using a thermal chemical vapor deposition method from the metalorganic compounds Li(C11H19O2) and Nb(OC2H5)5. The range of operating conditions for obtaining pure epitaxially grown LiNbO3 without other oxides is within that for obtaining pure polycrystalline LiNbO3 grown on silicon substrate. On analyzing the composition of the epitaxially grown LiNbO3 film, the composition of the film was similar to that of the LiNbO3 solid solution in the phase diagram of the Li-Nb composite oxide obtained for crystal growth from a molten solution. 相似文献
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Investigation of steps behavior on vicinal (111) surface during sublimation was carried out using 3D-model of diamond-like crystal. Step width periodic variations predicted by Schwoebel were found by modeling. Diamond-like crystal structure results in the asymmetry in atom fluxes to the upper or lower terraces, with the sign of asymmetry depending on the step structure. The essential effect of vacancies created on terraces on migration length of atoms was revealed. 相似文献
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Masahiko Hiratani Toshihide Nabatame Yuichi Matsui Shinichiro Kimura 《Thin solid films》2002,410(1-2):200-204
Platinum thin films grown by chemical vapor deposition (CVD) using a liquid precursor of (methylcyclopentadienyl)trimethylplatinum were characterized in terms of crystallographic nature, morphology, contaminants, and their influence on electrical properties. The lattice constant of these CVD films (3.91–3.92 Å) is smaller than that of bulk platinum. A high oxygen contaminant is observed, irrespective of the oxygen ratio during growth. A film grown at low oxygen content consists of randomly oriented micro-grains and contains a large amount of carbon contaminants. When the film is grown under oxidative conditions, it shows a 111-textured cylindrical morphology with increasing thickness. The electric resistivity is higher than the bulk standard, and it increases with decreasing oxygen ratio during the film growth. These results indicate that the carbon contaminant causes the randomly oriented micro-grains and contributes to the high residual resistivity. 相似文献
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Dongyun Guo Akihiko Ito Takashi Goto Rong Tu Chuanbin Wang Qiang Shen Lianmeng Zhang 《Journal of Materials Science: Materials in Electronics》2013,24(6):1758-1763
A TiO2 film was prepared on Pt/Ti/SiO2/Si substrate by a laser chemical vapor deposition method. The rutile TiO2 film with pyramidal grains and columnar cross-section was obtained at a high deposition rate (R dep = 11.4 μm h?1). At 300 K and 1 MHz, the dielectric constant (ε r) and loss (tanδ) of the TiO2 film were about 73.0 and 0.0069, respectively. The electrical properties of TiO2 film were investigated by ac impedance spectroscopy over ranges of temperature (300–873 K) and frequency (102–107 Hz). The Cole–Cole plots between real and imaginary parts of the impedance (Z′ and Z′′) in the above frequency and temperature range suggested the presence of two relaxation regimes that were attributed to grain and grain boundary responses. The ionic conduction in the rutile TiO2 film was dominated by the oxygen vacancies. 相似文献
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Tyler P. Martin 《Thin solid films》2008,516(5):681-683
Initiated chemical vapor deposition (iCVD) is a technique used to synthesize polymer thin films and coatings from the vapor phase in situ on solid substrates via free-radical mechanisms. It is a solventless, low-temperature process capable of forming very thin conformal layers on complex architectures. By implementing a combinatorial approach that examines five initiation temperatures simultaneously, we have realized at least a five-fold increase in efficiency. The combinatorial films were compared to a series of blanket films deposited over the same conditions to ensure the combinatorial system provided the same information. Direct synthesis from the vapor phase allows for in situ control of film morphology, molecular weight and crosslinking, and the combinatorial system decreases the time required to find the relationship between these interrelated properties. Some coatings were tested for antimicrobial performance against E. coli and B. subtilis. 相似文献