Thermochemical Nitridation of Microporous Silica Films in Ammonia

Microporous silicon dioxide thin Films were deposited on silicon substrates from a solution of tetraethoxysilane, ethanol, and water. These were converted to dense oxynitrides through a high-temperature reaction with ammonia. The ammonia treatments yielded amorphous, compositionally homogeneous films with overall nitrogen contents ranging up to 40 mol%. For ammonia treatments below 800°C, nitrogen was incorporated into the films as an amine species, whereas higher temperature treatments produced a nitride material.     

Improving the Efficiency of Multicrystalline Silicon by Adding an ARC Layer in the Front Device

High efficiency multicrystalline solar cells must improve performance while replacing higher cost monocrystalline silicon with lower cost multicrystalline silicon. Composite silicon dioxide-titanium dioxide (SiO₂?TiO₂) films are deposited on a large area of 15.6×15.6 cm² textured multicrystalline silicon solar cells to increase the incident light trapped within the device. This is being achieved through new cell device structures that improve light trapping and energy conversion capability. These new structures depend on passivated thick and thin layers of silicon dioxide and titanum dioxide grown via wet and dry thermal oxidation. By replacing dry oxidation with wet oxidation the temperatures process can be lowered from 1050^°C to 850^°C to reduce both cycle time and wafer damage.     

SiO2对TiO2薄膜性能的影响

采用溶胶-凝胶法分别制备出SiO2溶胶和TiO2溶胶,以不同的比例进行混胶。用旋涂法在载玻片上进行制膜。借助于紫外-可见光吸收光谱、原子力显微镜分析了SiO2/TiO2薄膜吸光性能和显微结构。通过对金黄葡萄菌和大肠杆菌的杀菌实验表明其杀菌率达99%以上。     

Crystallization of amorphous silicon thin films deposited by PECVD on nickel-metalized porous silicon

ABSTRACT: Porous silicon layers were elaborated by electrochemical etching of heavily doped p-type silicon substrates. Metallization of porous silicon was carried out by immersion of substrates in diluted aqueous solution of nickel. Amorphous silicon thin films were deposited by plasma-enhanced chemical vapor deposition on metalized porous layers. Deposited amorphous thin films were crystallized under vacuum at 750 [DEGREE SIGN]C. Obtained results from structural, optical, and electrical characterizations show that thermal annealing of amorphous silicon deposited on Ni-metalized porous silicon leads to an enhancement in the crystalline quality and physical properties of the silicon thin films. The improvement in the quality of the film is due to the crystallization of the amorphous film during annealing. This simple and easy method can be used to produce silicon thin films with high quality suitable for thin film solar cell applications.     

纳米二氧化钛薄膜制备方法研究进展

二氧化钛纳米晶薄膜优异的性能使其成为研究焦点,制备二氧化钛薄膜有着重要的现实意义。介绍了近年来国内外二氧化钛薄膜制备技术的研究进展,主要涉及高活性二氧化钛光催化薄膜的制备(制备方法包括溶胶-凝胶法、丝网印刷法、激光化学气相沉积法、水热结晶法、电泳法等),负载二氧化钛薄膜常用的载体,以及在环境保护等方面的应用研究现状,并指出以后的研究方向。     

复合硅源在大理石表面仿生合成二氧化硅保护膜的研究

使用硅酸钠/氟硅酸钠复合硅源,通过仿生合成方法在大理石表面制备得到了一层SiO2为主要成分的保护膜,并对该膜的性能进行了检测评价.运用傅里叶变换红外光谱仪和扫描电子显微镜对膜的结构和形貌进行了表征,探讨了SiO2的成膜机理.结果表明,运用复合硅源可在近中性条件下在大理石表面形成SiO2膜,SiO2颗粒以球形形态沉积在大理石表面,表现出成核、颗粒长大和颗粒堆聚3个阶段.24 h可形成较完整、均匀致密的保护层.该膜不仅具有优良的耐酸、耐候性,还具有良好的透气性能.     

Synthesis and Characterization of Nanostructured Cerium Dioxide Thin Films Deposited by Ultrasonic Spray Pyrolysis

Nanostructured thin films of cerium dioxide have been prepared on single-crystalline silicon substrates by ultrasonic spray pyrolysis using cerium acetylacetonate as a metal–organic precursor dissolved in anhydrous methanol and acetic acid as an additive. The morphology, structure, optical index, and electrical properties were studied by X-ray diffraction, scanning electron microscopy, atomic force microscopy, ellipsometry, and impedance spectroscopy. The use of additives is very important to obtain crack-free films. The substrate temperature and flow rate was optimized for obtaining smooth ( R _a<0.4 nm), dense ( n >2), and homogeneous nanocrystalline films with grain sizes as small as 10 nm. The influence of thermal annealing on the structural properties of films was studied. The low activation energy calculated for total conductivity (0.133 eV) is attributed to the nanometric size of the grains.     

铝酸锶荧光粉的表面包覆

本实验用Na2SiO3对铝酸锶进行二氧化硅包膜以改善其耐水性。检测结果表明,产品被二氧化硅完整紧密包覆,表现出优良的耐水性能。在纯水中,原样6小时内即完全水解,而包覆后的产品在48小时后无水解。同时,包膜对颜料的发光性能影响很小,发射光和激发光强度损失在1％左右。     

Ferroelectric and structural instability of (Pb,Ca)TiO3 thin films prepared in an oxygen atmosphere and deposited on LSCO thin films which act as a buffer layer

Structural, microstructural and ferroelectric properties of Pb_0.90Ca_0.10TiO₃ (PCT10) thin films deposited using La_0.50Sr_0.50CoO₃ (LSCO) thin films which serve only as a buffer layer were compared with properties of the thin films grown using a platinum-coated silicon substrate. LSCO and PCT10 thin films were grown using the chemical solution deposition method and heat-treated in an oxygen atmosphere at 700 °C and 650 °C in a tube oven, respectively. X-ray diffraction (XRD) and Raman spectroscopy results showed that PCT10 thin films deposited directly on a platinum-coated silicon substrate exhibit a strong tetragonal character while thin films with the LSCO buffer layer displayed a smaller tetragonal character. Surface morphology observations by atomic force microscopy (AFM) revealed that PCT10 thin films with a LSCO buffer layer had a smoother surface and smaller grain size compared with thin films grown on a platinum-coated silicon substrate. Additionally, the capacitance versus voltage curves and hysteresis loop measurement indicated that the degree of polarization decreased for PCT10 thin films on a LSCO buffer layer compared with PCT10 thin films deposited directly on a platinum-coated silicon substrate. This phenomenon can be described as the smaller shift off-center of Ti atoms along the c-direction 〈001〉 inside the TiO₆ octahedron unit due to the reduction of lattice parameters. Remnant polarization (P_r) values are about 30 μC/cm² and 12 μC/cm² for PCT10/Pt and PCT10/LSCO thin films, respectively. Results showed that the LSCO buffer layer strongly influenced the structural, microstructural and ferroelectric properties of PCT10 thin films.     

The tribological characteristics of phosphorylated 3‐aminopropyltriethoxysilane nanometer film

Thin films deposited on the phosphonate 3‐aminopropyltriethoxysilane (APTES) self‐assembled monolayer (SAM) were prepared on the hydroxylated silicon substrate by a self‐assembling process from specially formulated solution. Chemical compositions of the films and chemical state of the elements were detected by X‐ray photoelectron spectrometry. The thickness of the films was determined with an ellipsometer, whereas the morphologies and nanotribological properties of the samples were analyzed by means of atomic force microscopy. As the results, the target film was obtained and reaction may have taken place between the thin films and the silicon substrate. It was also found that the thin films showed the lowest friction and adhesion followed by APTES‐SAM and phosphorylated APTES‐SAM, whereas silicon substrate showed high friction and adhesion. Microscale scratch/wear studies clearly showed that thin films were much more scratch/wear resistant than the other samples. The superior friction reduction and scratch/wear resistance of thin films may be attributed to low work of adhesion of nonpolar terminal groups and the strong bonding strength between the films and the substrate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Morphological study of thin films: Simulation and experimental insights using horizontal visibility graph

We studied the morphological nature of various thin films such as silicon carbide (SiC), diamond (C), germanium (Ge), and gallium nitride (GaN) on silicon substrate Si(100) using the pulsed laser deposition (PLD) method and Monte Carlo simulation. We, for the first time, systematically employed the visibility algorithm graph to meticulously study the morphological features of various PLD grown thin films. These thin-film morphologies are investigated using random distribution, Gaussian distribution, patterned heights, etc. The nature of the interfacial height of individual surfaces is examined by a horizontal visibility graph (HVG). It demonstrates that the continuous interfacial height of the silicon carbide, diamond, germanium, and gallium nitride films are attributed to random distribution and Gaussian distribution in thin films. However, discrete peaks are obtained in the brush and step-like morphology of germanium thin films. Further, we have experimentally verified the morphological nature of simulated silicon carbide, diamond, germanium, and gallium nitride thin films were grown on Si(100) substrate by pulsed laser deposition (PLD) at elevated temperature. Various characterization techniques have been used to study the morphological, and electrical properties which confirmed the different nature of the deposited films on the Silicon substrate. Decent hysteresis behavior has been confirmed by current-voltage (IV) measurement in all the four deposited films. The highest current has been measured for GaN at ～60 nA and the lowest current in SiC at ～30 nA level which is quite low comparing with the expected signal level (μA). The HVG technique is suitable to understand surface features of thin films which are substantially advantageous for the energy devices, detectors, optoelectronic devices operating at high temperatures.     

Preparation, structural and optical characterization of BaWO4 and PbWO4 thin films prepared by a chemical route

Polycrystalline BaWO₄ and PbWO₄ thin films having a tetragonal scheelite structure were prepared at different temperatures. Soluble precursors such as barium carbonate, lead acetate trihydrate and tungstic acid, as starting materials, were mixed in aqueous solution. The thin films were deposited on silicon, platinum-coated silicon and quartz substrates by means of the spinning technique. The surface morphology and crystal structure of the thin films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, and specular reflectance infrared Fourier transform spectroscopy, respectively. Nucleation stages and surface morphology evolution of thin films on silicon substrates have been studied by atomic force microscopy. XRD characterization of these films showed that BaWO₄ and PbWO₄ phase crystallize at 500 °C from an inorganic amorphous phase. FTIR spectra revealed the complete decomposition of the organic ligands at 500 °C and the appearance of two sharp and intense bands between 1000 and 600 cm⁻¹ assigned to vibrations of the antisymmetric stretches resulting from the high crystallinity of both thin films. The optical properties were also studied. It was found that BaWO₄ and PbWO₄ thin films have Eg=5.78 eV and 4.20 eV, respectively, of a direct transition nature. The excellent microstructural quality and chemical homogeneity results confirmed that soft solution processing provides an inexpensive and environmentally friendly route for the preparation of BaWO₄ and PbWO₄ thin films.     

A New Method to Evaluate Thin Film Adhesion

This paper discusses a new method of evaluating thin film adhesion both qualitatively and quantitatively via a combination of peeling and image processing techniques. The adhesion of thin film on the entire substrate can be quickly evaluated and quantified to a continuous response variable which is superior to a discrete response variable as described in the ASTM D3359-78 publication. Feasibility of this technique has been demonstrated through a gauge capability study which resulted in 2.7% P/T (precision to tolerance) ratio at six sigma standard deviation for a tolerance of 100. Experimental results using the proposed method to evaluate the process/property relationship of aluminum films as deposited onto various dielectric substrates such as polyimide, silicon dioxide, and silicon nitride have been obtained and have been shown to agree with conventional stud pull test results. The estimated cycle time to evaluate thin film adhesion is five minutes per 4-inch size wafer once the sample is prepared. This short process cycle time and proven reliability show that there is merit in implementing this technique both in the laboratory for process development and in the factory for statistical process control of products.     

Contents Lists and Abstracts from the Journal of the Adhesion Society of Japan

This paper discusses a new method of evaluating thin film adhesion both qualitatively and quantitatively via a combination of peeling and image processing techniques. The adhesion of thin film on the entire substrate can be quickly evaluated and quantified to a continuous response variable which is superior to a discrete response variable as described in the ASTM D3359-78 publication. Feasibility of this technique has been demonstrated through a gauge capability study which resulted in 2.7% P/T (precision to tolerance) ratio at six sigma standard deviation for a tolerance of 100. Experimental results using the proposed method to evaluate the process/property relationship of aluminum films as deposited onto various dielectric substrates such as polyimide, silicon dioxide, and silicon nitride have been obtained and have been shown to agree with conventional stud pull test results. The estimated cycle time to evaluate thin film adhesion is five minutes per 4-inch size wafer once the sample is prepared. This short process cycle time and proven reliability show that there is merit in implementing this technique both in the laboratory for process development and in the factory for statistical process control of products.     

复合二氧化钛负载膜降解十二烷基苯磺酸钠的研究

以玻璃珠为载体,用溶胶-凝胶法制备二氧化钍和三氧化二钕复合二氧化钛膜对水溶液中的十二烷基苯磺酸钠进行了固定相光催化氧化实验。研究了复合膜的紫外-可见光透过性能和二氧化钍与三氧化二钕的掺杂量、十二烷基苯磺酸钠水溶液的pH值等因素对光解率的影响。结果表明,二氧化钍和三氧化二钕复合二氧化钛负载膜的光催化活性显著提高且组分质量比存在最佳值。当二氧化钍与二氧化钛的质量比为0.02,三氧化二钕与二氧化钛的质量比为0.01时,最高光解率分别为同样条件下二氧化钛的2.3倍和1.6倍。     

Electron Cyclotron Resonance Plasma-Enhanced Metalorganic Chemical Vapor Deposition of Tantalum Oxide Thin Films on Silicon near Room Temperature

Films of tantalum oxide, ranging in thickness from 25 to 2000 nm, were successfully deposited on silicon by the electron cyclotron resonance plasma-enhanced metalorganic chemical vapor deposition (ECR-MOCVD) process at deposition rates of up to 33 nm/min. The films were produced by decomposition of tantalum pentaethoxide into tantalum oxide in an oxygen ECR microwave plasma. The films were amorphous (but fully dense) since the temperature of the substrate, which was unheated, was estimated to be 76–120°C. The growth of the tantalum oxide films was accompanied by the formation of an interlayer of silicon dioxide at the silicon interface. The tantalum oxide films were oxygen rich (relative to Ta₂O₅). The effective relative dielectric constant of these dual-layer dielectrics ranged from ɛ_ef= 8.5 to 24; this range was explained in terms of a bilayer consisting of a 13-nm-thick silicon dioxide layer of ɛ_sx= 4, and a tantalum oxide overgrowth of varying thickness having ɛ_tx∼ 25. A maximum breakdown strength of the films was 6.9 MV/cm and the leakage current at a field of 1 MV/cm was 3.0 × 10^-8. The breakdown properties were related to the presence of stray particles on the substrate; these properties are expected to improve considerably if the processing is carried out in a clean-room environment. The silicon dioxide layer is believed to have grown by the diffusion of oxygen through the tantalum oxide overlayer despite the low substrate temperature.     

Characterization on polymerized thin films for low-k insulator using PECVD

Plasma polymerized cyclohexane and TEOS hybrid thin films have been deposited on silicon substrates at room temperature with varying RF power by plasma-enhanced chemical vapor deposition (PECVD) method. As-grown thin films were annealed in vacuum. Cyclohexane monomer was utilized as organic precursor and TEOS monomer as inorganic precursor. Hydrogen and argon were used as bubbler and carrier gases, respectively. The as-grown plasma polymerized hybrid thin films were analyzed by FT-IR spectroscopy, hardness and modulus measurements, and electrical properties. Annealed hybrid thin films were also analyzed. The dielectric constant of thin films increases with increasing plasma power.     

Annealing Temperature Effect on Bismuth Induced Crystallization of Hydrogenated Amorphous Silicon Thin Films

Silicon - In this work, we emphasis on the Bismuth induced crystallization of hydrogenated amorphous silicon (a-Si) thin films. 50&nbsp;nm of bismuth thin films are deposited by vapor...     

Quantitative measurement of chromium's ability to promote adhesion

Using atomic force spectroscopy, we investigated the adhesion-promoting ability of chromium. An intermediate layer of chromium can overcome the low adhesion between metal films and silicon dioxide. For the first time, we quantitatively studied this experimentally well known fact. We compared the adhesion between chromium and different substrates such as gold, silver, mica, and silicon dioxide and, beyond that, the adhesion between silicon dioxide and the same substrates. To avoid additional effects due to water, we chose ethanol as a nonpolar solvent. Taking the interfacial energies of the surfaces with the liquid into account eliminates the direct influence of the fluid medium on the adhesion of the solid material. The results we obtained corroborate the experimental fact of higher adhesion of chromium with the chosen substrates, as well as substantiate the value of chromium as an adhesion promoter. The adhesion of chromium-coated probes on gold, silicon dioxide, and mica is higher than the adhesion of silicon dioxide probes on the same substrates.     

染料敏化太阳能电池光阳极制备及其应用

本文采用二氧化钛(P25),粘结剂及溶剂,研磨数小时得到均匀分散的纳米二氧化钛浆料,通过涂布法在FTO导电玻璃衬底上制备了光阳极,并用其组装成染料敏化太阳能电池。经过优化二氧化钛和粘结剂的比例,得到平整、致密、均匀的二氧化钛薄膜。对二氧化钛薄膜进行FTIR、SEM和光学显微镜表征,并对组装电池进行光电性能测试,研究了二氧化钛浆料不同制备条件对太阳能电池性能的影响。结果表明,二氧化钛粉末和粘结剂质量比为4∶3时,制备的二氧化钛浆料稳定性高;涂布厚度为20μm时,电池性能较好。组装的染料敏化太阳能电池在100mW/cm2模拟太阳光照下,光电转换效率达到2.51%。