光学薄膜低压反应离子镀技术初探

光学薄膜低压大电流反应离子镀技术是近年来光学镀膜技术领域中的最新进展。在国内系统地开展这方面的研究尚未见报。本文叙述了低压大电流反应离子镀技术的基本原理与成膜特点，介绍了我们建立的实验系统，特别是有关低压大电流等离子体源的各种实验参数，给出了应用该技术制备的两种常用薄膜的光学和机械特性的初步结果。     

Optimization of the process for preparing Al-doped ZnO thin films by sol-gel method

Transparent and conducting Al-doped ZnO thin films with c-axis-preferred orientation were prepared on glass substrate via sol-gel route. The physical and chemical changes during thermal treatment were analyzed by TG-DSC spectra and the crystallization quality was characterized by XRD patterns. The optimized preheating and post-heating temperatures were determined at ~420℃ and ~530℃, respec-tively. From thermodynamic and kinetics views, we investigated the mechanism of orientation growth with (002) plane parallel to the substrates. The surface morphologies of the films, post-heated at 420℃, 450℃, 530℃ and 550℃, respectively, were observed by SEM micrographs. The film post-heated at 530℃ shows a homogenous dense microstructure and exhibits the minimum sheet resistance of 140 Ω/Sq. The visible optical transmittance of all the films is beyond 90%. In addition, the annealing treatment in vacuum can contribute greatly to the electrical conductivity.     

Influence of bath composition on the electrodeposition of cobalt-molybdenum amorphous alloy thin films

Cobalt-molybdenum (Co-Mo) amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters, only the concentration ratio of molybdate to cobalt ions ([ MoO2-4 ]/[CO2 ]) was varied to analyze its influence on the mechanism of induced cobalt-molybdenum codeposition. Voltammetry was one of the main techniques, which was used to examine the voltammetric response, revealing that cobalt-molybdenum codeposi-tion depended on the nature of the species in solution. To correlate the type of the film to the electrochemical response, various co-bait-molybdenum alloy thin films obtained from different [ MoO2-4]/[Co2 ] solutions were tested. Crack-free homogeneous films could be easily obtained from the low molybdate concentrations ([ MoO2-4]/[Co2 ]≈0.05) applying low deposition potentials.Moreover, the content of molybdenum up to 30wt% could be obtained from high molybdate concentration; in this case, the films showed cracks. The formation of these cracked films could be predicted from the observed distortions in the curves of electric cur-rent-time (j-t) deposition transients. The films with amorphous stmeture were obtained. The hysteresis loops suggested that the easily film were obtained when the deposition potential was -1025 mV, and [ MoO2-4]/[Co2 ] was 0.05 in solution, which exhibited a nicer soft-magnetic response.     

Evolution of insoluble eutectic Si particles in anodic oxidation films during adipic-sulfuric acid anodizing processes of ZL114A aluminum alloys

The effects of insoluble eutectic Si particles on the growth of anodic oxide films on ZL114A aluminum alloy substrates were in-vestigated by optical microscopy (OM) and scanning electron microscopy (SE...     

Ductility of metal thin films in flexible electronics

Flexible, large area electronics using various organic and inorganic materials are beginning to show great promise. During manufacture and service, large deformation of these hybrid materials will pose significant challenges in terms of high performance and reliability. A deep understanding of the ductility or flexibility of macroelectronics becomes one of the major issues that must be addressed urgently. This paper describes the current level of understanding on the thin-film ductility, both free-standing and substrate-supported, and relevant influencing factors. Supported by the National Basic Research Program of China (Grant No. 2004CB619303), the 111 Project of China (Grant No. B06025), and the Science and Technology Key Project from Ministry of Education of China (Grant Nos. 02182, 03182)     

绝缘体上硅锗薄膜的退火研究

绝缘体上硅锗是近年来受到人们广泛关注和研究的新型微电子材料,它以其独特的全介质隔离结构,可为研发新型的超高速、低功耗、抗辐射、高集成度硅基器件和芯片提供一种新的解决方案,有希望成为突破体硅器件的物理极限、在深亚微米超大规模集成电路芯片主流技术中获得广泛地应用。介绍了我们制备绝缘体上硅锗薄膜的方法和结果。     

Highfield effects of layered perovskite ferroelectric thin films

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基于拉曼光谱的类金刚石薄膜的热稳定性研究

利用阴极真空弧放电设备制备了表面光滑的类金刚石薄膜材料,通过多波长激发的拉曼光谱研究了不同退火条件下所制薄膜的热稳定性.实验结果表明,在小于400℃的温度处理下,类金刚石薄膜微观结构几乎不发生变化,薄膜处于稳定区;当温度升高至600℃,微观结构开始发生微妙的变化,认为处于亚稳定区;当温度升至800℃甚至1 000℃时,类金刚石薄膜的微观结构发生显著变化,薄膜开始出现石墨化,物理性质不能保持稳定.     

磁性薄膜自旋重取向的机制

采用Monte Carlo方法,使用微观电子自旋模型和具有偶极相互作用的Heisenberg模型,对16×16二维平方格子的磁性系统自旋重取向现象进行了研究.发现在一定参数下,系统呈现出包含4个不同区域的磁化曲线.从理论上再现了系统从垂直磁化向面内磁化转变时的宏观磁矩的丢失现象,得到了与实验观测相一致的结果.通过计算系统的自旋组态和能量特征,对产生这种现象的机制进行了分析.     

不同微观形貌的ZnO薄膜的制备及其表征

通过溶胶凝胶法在透明玻璃上制备了ZnO薄膜,分别采用XRD、SEM和AFM等分析方法对所制样品进行表征,分析了样品的结构特性。研究了络合剂及添加剂等因素对ZnO薄膜微观形貌的影响,并且考察了不同计量比下ZnO颗粒的富集程度、纳米线的对称程度差别,得到了致密粒子(0.7μm)和纳米线(0.5μm)的两种微观结构ZnO薄膜。研究表明,纳米线呈倒伏状分布在基体表面,并分析了对称分布的纳米线结构产生的机理。     

工作气压对氮化硼薄膜场发射特性的影响

利用射频磁控溅射方法，在n型(100)Si基底上沉积了氮化硼(BN)薄膜，并在超高真空系统中测量了BN薄膜的场发射特性．研究发现，沉积时工作气压的变化对BN薄膜的场发射特性有很大影响，工作气压为2Pa时沉积的BN薄膜样品的场发射特性较好，其阈值电场为6V/μm，场发射电流为320μA／cm^2．F—N曲线表明，在外加电场的作用下，电子是通过隧道效应穿透BN薄膜表面势垒发射到真空的．     

微波辐射制备TiO2薄膜光催化性能研究

采用微波辐射法由溶胶制备出TiO2薄膜,用XRD和TEM对催化剂进行了表征。以甲基橙为模拟污染物,考察了微波功率和膜层厚度对TiO2光催化活性的影响,并实际考察了TiO2薄膜对啤酒废水的降解效果。结果表明：制备的TiO2薄膜具有较高光催化活性,微波功率300W时光催化活性最大,对啤酒废水具有良好的处理效果。     

3C—SiC单晶薄膜的干法刻蚀研究

以四氟化碳（CF4）和CF4 O2作为刻蚀气体,对外延3C-SiC单晶薄膜进行了系统的等离子体刻蚀研究。结果表明薄膜刻蚀速率在气体流量一定的情况下与O2/CF4流量比有关：当O2/CF4流量比为40%左右时,刻蚀速率达到量大值;O2/CF4流量比低于40%,不仅刻蚀速度降低而且还在被刻蚀样品表面形成暗表面层,俄歇能谱（AES）分析表明暗层为富C表面的的残余SiC,AES分析还证实改变工艺条件可以消除富C表面的文中还给出了经图形刻蚀后的样品的表面形貌（SEM）照片。     

微波辐射制备TiO_2薄膜光催化性能研究

采用微波辐射法由溶胶制备出TiO2薄膜,用XRD和TEM对催化剂进行了表征。以甲基橙为模拟污染物,考察了微波功率和膜层厚度对TiO2光催化活性的影响,并实际考察了TiO2薄膜对啤酒废水的降解效果。结果表明:制备的TiO2薄膜具有较高光催化活性,微波功率300 W时光催化活性最大,对啤酒废水具有良好的处理效果。     

Preparation and Properties of IrO2 Thin Films Grown by Pulsed Laser Deposition Technique

Highly conductive IrO2 thin films were prepared on Si （100） substrates by means of pulsed laser deposition technique from an iridium metal target in an oxygen ambient atmosphere. Emphasis was put on the effect of oxygen pressure and substrate temperature on the structure, morphology and resistivity of IrO2 films. It was found that the above properties were strongly dependent on the oxygen pressure and substrate temperature. At 20 Pa oxygen ambient pressure, pure polycrystalline IrO2 thin films were obtained at substrate temperature in the 300-500℃ range with the preferential growth orientation of IrO2 films changed with the substrate temperature. IrO2 films exhibited a uniform and densely packed granular morphology with an average feature size increasing with the substrate temperature. The room-temperature resistivity variations of IrO2 films correlated well with the corresponding film morphology changes. IrO2 films with the minimum resistivity of （42 ±6）μΩ·cm was obtained at 500℃.     

Effect of Ag addition on the microstructure and magnetic properties of FePt thin films

FePt thin films and [FePt/Ag]n multilayer thin films were prepared by magnetron sputtering technique and subsequent annealing process. By comparing the microstructure and magnetic properties of these two kinds of thin films, effects of Ag addition on the structure and properties of FePt thin films were investigated. Proper Ag addition was found helpful for FePt phase transition at lower annealing temperature. With Ag addition, the magnetic domain pattern of FePt thin film changed from maze-like pattern to more discrete island-like domain pattern in [FePt/Ag]n multilayer thin films. In addition, introducing nonmagnetic Ag hindered FePt grains from growing larger. The in-depth defects in FePt films and [FePt/Ag]n multilayer films verify that Ag addition is attributed to a large number of pinning site defects in [FePt/Ag]n film and therefore has effects on its magnetic properties and microstructure.     

基底偏压对BN薄膜场发射特性的影响

利用射频磁控溅射方法，在n型(100)Si基底上沉积了氮化硼薄膜(BN)．通过分析电流密度-电场强度曲线，发现BN薄膜的场发射特性与基底偏压影响很大，基底偏压为-140V时BN薄膜样品场发射特性要好于其它样品，阈值电场低于8V／μm．F-N曲线表明：电子是通过隧道效应克服BN薄膜表面势垒发射到真空的．     

Photoluminescence properties of ZnO thin films prepared by DC magnetron sputtering

ZnO thin films were prepared by direct current（DC） reactive magnetron sputtering under different oxygen partial pressures And then the samples were annealed in vacuum at 450 ℃. The effects of the oxygen partial pressures and the treatment of annealing in vacuum on the photoluminescence and the concentration of six intrinsic defects in ZnO thin films such as oxygen vacancy（Vo）, zinc vacancy（VZn）, antisite oxygen（OZn）, antisite zinc（Zno）, interstitial oxygen（Oi） and interstitial zinc（Zni） were studied. The results show that a green photoluminescence peak at 520 nm can be observed in all the samples, whose intensity increases with increasing oxygen partial pressure; for the sample annealed in vacuum, the intensity of the green peak increases as well. The green photoluminescence peak observed in ZnO may be attributed to zinc vacancy, which probably originates from transitions between electrons in the conduction band and zinc vacancy levels, or from transitions between electrons in zinc vacancy levels and up valence band.     

Investigation on inductive heating of A356 alloy for thixo-forming

To meet the demands of continuous stream-line for component production in the thixo-forming industry, billet heating should be of high quality and in a controllable way. A 4-step inductive heating strategy for aluminum alloy A356 was performed. Thixotropic testing and microstructure analysis showed that a homogenous temperature distribution was achieved after tempera-ture-power-time optimization. Theoretical analysis was given concerning the thermal conductivity and heat capacity of A356 be-tween conventional and semisolid casting microstructures. The experimental results show that the optimized 4-step strategy could bethe best strategy for billet heating during the thixo-forming of aluminum alloy A356.     

Investigations of ZnO thin films deposited by a reactive pulsed laser ablation

Highly transparent ZnO thin films were deposited at different substrate temperatures by pulsed laser deposition in an oxygen atmosphere. The thin films were characterized by various techniques including X-ray diffraction, scanning electron microscopy, optical absorption, and photoluminescence. We demonstrated that oriented wurtzite ZnO thin films could be deposited at room temperature using a high purity zinc target. Variable temperature photoluminescence revealed new characteristics in the band edge emission. The underlying mechanism for the observed phenomena was also discussed.