YBCO高温超导薄膜激光化学腐蚀进程的实验观测

提出了将激光辅助化学刻蚀技术应用于钇钡铜氧(YBCO)高温超导薄膜的刻蚀,研究了无掩膜YBCO薄膜激光化学刻蚀的表面特性及其变化规律,在激光辐照下,YBCO薄膜的液相刻蚀速率大大加快,并且在整个过程中,刻蚀速率呈现加快趋势,这一特性将有可能用于改善YBCO刻蚀中的横向钻蚀情况,并提高图形边缘的侧壁陡峭度.     

激光诱导液相电极腐蚀新方法

提出了一种激光诱导液相腐蚀新方法—电极腐蚀法。电极腐蚀法是指进行激光化学液相腐蚀时,在腐蚀溶液中添加电极,以吸引反应中间离子脱离基片表面,实现腐蚀的持续稳定进行。理论分析和实验结果都表明,电极腐蚀法可以有效地加快激光腐蚀的进程;吸附在基片表面的离子在电极作用下,快速迁移出基片表面,保证了基片表面腐蚀溶液构成的稳定,进而得到更加均匀的腐蚀表面;利用电流随腐蚀速率变化而变化的特点,使腐蚀速率和深度的直接监控转变为对腐蚀电流的间接控制,简化腐蚀控制方法。基于以上优点,电极腐蚀法可以克服现有激光腐蚀方法的诸多弊端,改善激光腐蚀性能,在特殊结构光电器件的制作和半导体的微细加工中具有广阔的应用前景。     

基于外加热激励源的中红外激光辐照VO2薄膜温升研究

VO_2薄膜在中红外激光防护领域有着重要意义。为研究中红外激光辐照VO_2薄膜的温升累积效应及克服中红外激光器功率过小的困难,设计了一种外加热激励源的实验方法。首先利用ANSYS软件对中红外纳秒脉冲激光在不同激励源温度和不同功率密度下辐照VO_2薄膜的温升累积进行仿真,并做了实际验证。研究发现,随着外加激励温度的升高,可在一定时间(100s)内达到VO_2相变温度的激光功率密度逐渐减小,通过增加功率密度,也可以进一步降低相变所需的激励源温度。两者均提高了VO_2薄膜的温升速率。然后在激励源温度为40℃、中红外激光功率密度为1 W/mm~2的条件下研究了中红外纳秒脉冲激光参数对VO_2薄膜的温升累积效应,结果表明,增加激光脉宽、增加重频或光斑半径均能有效增加VO_2薄膜的温升速率。     

响应曲面法研究碳钢在模拟烟气冷凝液中的腐蚀行为

电厂烟气冷凝液有较强腐蚀性,引起腐蚀的因素较多。采用响应曲面法研究了模拟烟气冷凝液中影响腐蚀的主要因素pH值、Cl-浓度与温度对碳钢腐蚀速率的影响,通过单因素极化曲线测定了碳钢的腐蚀电流密度。结果表明:随着溶液pH值的降低、Cl-浓度的增大和溶液温度的升高,腐蚀电流密度增大。在此基础上,运用响应曲面法中的BBD模型设计试验条件,测试并分析了碳钢在不同条件下的腐蚀速率,发现对碳钢腐蚀速率的影响程度从大到小依次为pH值﹥温度﹥Cl-浓度。     

用于GaSb/AlGaAsSb器件制备的新型化学腐蚀液研究

提出了一种适用于GaSb/AlGaAsSb器件工艺的由氢氟酸、酒石酸和双氧水构成的氢氟酸系腐蚀液。该腐蚀液对于GaSb和AlGaAsSb材料具有良好的腐蚀特性和稳定的刻蚀速率。选用合适的溶液组份可以得到较低的刻蚀速率,有利于在器件工艺中进行精确控制。实验中发现该腐蚀液对AlGaAsSb的腐蚀速率与其Al组份呈抛物线关系,在合适的Al组份下可对AlGaAsSb和GaSb两种材料进行非选择性的刻蚀。     

多晶硅太阳电池表面激光织构工艺研究

采用激光刻蚀,辅以化学溶液腐蚀对多晶硅片进行了表面织构.利用扫描电镜(SEM)、Helios LAB-rc反射率测试仪和Semilab WT2000少子寿命仪对样品进行了表征.结果表明,多晶硅表面经激光织构后表现出很好的陷光效果,反射率降低为8.0％.激光织构使硅片的少子寿命缩短,通过沉积Al2O3钝化薄膜可改善多晶硅片的电学性能.     

在半导体和聚合物基片上激光诱发沉积

常规电镀液中用激光照射来代替电流,在半导体和聚合物基片上沉积金和钯-镍.镀层厚度取决于激光能量的强度从几百埃到几微米变化.在n型硅和砷化镓上金沉积显示出Schottky壁垒接触特性. 近来激光诱发所诱导的化学和电化学反应已引起很大注意,这种反应可能用于微电子装置中的沉积或刻蚀过程.金属化学镀和电镀过程用激光增强微电流,连续的氩离子激光束提高了沉积速率.用10~7～10~9W/cm~2(脉冲持续时间7～150毫微秒)激光辐照诱导金属或合金在电镀溶液中的半导体基     

UV激光刻蚀BOPP薄膜包装特性研究

目的研究UV激光刻蚀双向拉伸聚丙烯(BOPP)薄膜后分子结构的变化,分析UV激光刻蚀对薄膜结构及透氧、透湿和力学性能等包装性能的影响,以便更好应用于食品包装领域。方法通过激光扫描显微镜分析、红外光谱分析和拉曼光谱分析,研究不同刻蚀深度薄膜表面形貌及内部分子结构变化。结果红外光谱无变化,说明无新的非极性键产生,拉曼光谱出现荧光,在1613 cm-1处的特征峰说明C=C双键出现;激光刻蚀处理可以提高薄膜透氧和透湿性能,且随刻蚀深度增加而增加,薄膜正向氧气透过性大于反向,反向水蒸气透过性大于正向;薄膜机械性能下降,刻蚀线方向与拉伸方向垂直时,其力学性能下降要大于刻蚀线方向与拉伸方向平行。结论在使用UV激光刻蚀薄膜进行包装设计时须考虑薄膜方向以及刻蚀线方向。     

YBCO高温超导微带线的非线性光响应特性实验及其应用分析

研究了在波长为0.68μm的连续激光辐照下, YBCO高温超导薄膜微带线结构的光致非线性效应,并从实验现象和高温超导光响应器件研制两个角度进行讨论.主要的研究结果如下:高温超导薄膜微带线结构的非平衡光响应存在阈值,在本实验条件下,当功率＜15mW时,以辐射热效应为主;当功率＞15mW时,出现非平衡光响应.该阈值的获得,对光响应超导器件的设计与制作具有重要指导意义.在此基础之上,设想了一种新型的高温超导衰减器;另外,在反复通断激光实验中,观察到YBCO微带线具有时间累积的记忆效应,从而导致回复时间的出现.该现象也是影响高温超导光响应器件性能的重要因素之一,对非线性光响应超导器件的发展具有重要价值.     

电化学方法研究腐蚀介质对热浸镀Al-Zn-Si-RE合金镀层腐蚀行为的影响

为研究腐蚀介质对热浸镀Al-Zn-Si-RE合金镀层腐蚀行为的影响,利用电位-时间曲线、Tafel曲线和电化学阻抗谱技术研究了合金镀层在不同盐度、温度和pH值的NaCl溶液中的电化学腐蚀行为,利用扫描电子显微镜(SEM)观察不同腐蚀介质下极化测试后合金镀层的腐蚀形貌.结果表明:随着NaCl溶液温度或浓度的提高,热浸镀Al-Zn-Si-RE合金镀层均出现腐蚀电位负移、镀层腐蚀倾向增大、腐蚀速率增加、腐蚀抗力降低的现象;此外,酸性和碱性条件均会加快镀层在NaCl溶液中的腐蚀速率,其中镀层在pH值为11.0的碱性条件下,腐蚀电流最大,阻抗谱容抗弧幅值最小,说明镀层腐蚀速率最快,耐蚀性最差.     

Metal‐Assisted Chemical Etching of Silicon: A Review

This article presents an overview of the essential aspects in the fabrication of silicon and some silicon/germanium nanostructures by metal‐assisted chemical etching. First, the basic process and mechanism of metal‐assisted chemical etching is introduced. Then, the various influences of the noble metal, the etchant, temperature, illumination, and intrinsic properties of the silicon substrate (e.g., orientation, doping type, doping level) are presented. The anisotropic and the isotropic etching behaviors of silicon under various conditions are presented. Template‐based metal‐assisted chemical etching methods are introduced, including templates based on nanosphere lithography, anodic aluminum oxide masks, interference lithography, and block‐copolymer masks. The metal‐assisted chemical etching of other semiconductors is also introduced. A brief introduction to the application of Si nanostructures obtained by metal‐assisted chemical etching is given, demonstrating the promising potential applications of metal‐assisted chemical etching. Finally, some open questions in the understanding of metal‐assisted chemical etching are compiled.     

Characterization of etch pit formation via the Everson-etching method on CdZnTe crystal surfaces from the bulk to the nanoscale

A combination of atomic force microscopy, optical microscopy, and mass spectrometry was employed to study CdZnTe crystal surface and used etchant solution following exposure of the CdZnTe crystal to the Everson etch solution. We discuss the results of these studies in relationship to the initial surface preparation methods, the performance of the crystals as radiation spectrometers, the observed etch pit densities, and the chemical mechanism of surface etching. Our results show that the surface features that are exposed to etchants result from interactions with the chemical components of the etchants as well as pre-existing mechanical polishing.     

AgInSbTe相变薄膜的热刻蚀腐蚀特性

研究了AgInSbTe相变薄膜作为一种新的热刻蚀材料的腐蚀特性。采用射频磁控溅射的方法在室温下制备了非晶态AgInSbTe薄膜, 经真空加热退火晶化. 以氢氧化钠溶液作为腐蚀剂, 研究了退火温度、腐蚀剂浓度、腐蚀时间对晶态、非晶态 AgInSbTe薄膜腐蚀特性的影响. 结果表明: 以非晶态形式存在的沉积态AgInSbTe薄膜在0.001 mol/L氢氧化钠溶液中腐蚀速度小于0.04 nm/min, 退火晶化后, 薄膜的腐蚀速度大幅度提高, 晶态和非晶态薄膜的腐蚀选择比随退火温度的升高而增大. 当腐蚀时间为20 min时, 经300℃真空退火的晶态AgInSbTe薄膜比相应非晶态的腐蚀速度高45倍以上. 腐蚀后薄膜表面质量良好(粗糙度＜1 nm, 10 μm×10 μm区域). 并对AgInSbTe相变薄膜的腐蚀机理进行了讨论.     

Dissolution kinetics of MgO crystals in aqueous acidic salt solutions

The revelation and morphology of dislocation etch pits as well as the rates of macroscopic dissolution and selective etching on the {1 0 0} plane of MgO crystals in aqueous solutions of various inorganic salts are investigated in relation to the nature and concentration of salt in solution and the etching temperature. It is found that addition of a salt generally facilitates etch pit formation and that the rates of surface dissolution and selective etching increase with additive concentration, etchant temperature and character and ageing of dislocations, while the etch pit morphology depends on the concentration and chemical nature of an impurity, etching temperature and the ageing of the dislocations. It is also observed that some fast etching solutions produce very shallow etch pits at screw dislocations. The results are discussed from a consideration of solution pH, standard electrode potentials of metals and stability of complexes present in solution. The importance of the surface entropy factor in revealing etch pits at screw dislocations is pointed out.     

Patterning crystalline indium tin oxide by high repetition rate femtosecond laser-induced crystallization

A method is proposed for patterning crystalline indium tin oxide (c-ITO) patterns on amorphous ITO (a-ITO) thin films by femtosecond laser irradiation at 80 MHz repetition rate followed by chemical etching. In the proposed approach, the a-ITO film is transformed into a c-ITO film over a predetermined area via the heat accumulation energy supplied by the high repetition rate laser beam, and the unirradiated a-ITO film is then removed using an acidic etchant solution. The fabricated c-ITO patterns are observed using scanning electron microscopy and cross-sectional transmission electron microscopy. The crystalline, optical, electrical properties were measured by X-ray diffraction, spectrophotometer, and four point probe station, respectively. The experimental results show that a high repetition rate reduces thermal shock and yields a corresponding improvement in the surface properties of the c-ITO patterns.     

Investigations of surface layers produced by chemical treatment of GaP

The composition and structure of etched (100) GaP surfaces were studied just after etching and during aging. The two etchants, aqua regia and bromine in methanol, act through diffusion-limited and kinetically controlled processes respectively. The surface layer was found to have a substoichiometric oxide composition. The structural state of the surface etched with aqua regia could be explained by the chemical behaviour of the gallium ions in the aqueous medium, i.e. amorphous and porous surface layers containing water were produced at room temperature, whilst a dense crystalline water free layer was formed at boiling temperature. The bromine etchant also produced a water free surface. Just after etching (1.5–2) × 10¹⁵ O atoms cm^-2 and about 2 × 10¹⁵ disordered Ga atoms cm^-2 were produced by the acid etchant on the surface (determined by backscattering analysis). These values were not dependent on the etching temperature, in agreement with the diffusion-limited character of the aqua regia action.     

硬铝合金的侵蚀方法及技巧

针对硬铝合金样品组织显示困难及第二相侵蚀脱落等问题，提出了合理选择侵蚀剂、控制侵蚀过程出现的气泡逸出、注意侵蚀结束前的表面清洁和严格掌握侵蚀时间等方法。     

电催化金属辅助化学刻蚀法制备硅纳米线/多孔硅复合结构

量子限制效应使硅纳米线具有良好的场致发射特性,结合多孔硅的准弹道电子漂移模型可提高场发射器件的性能.传统的金属辅助化学刻蚀法制备硅纳米线的效率较低,本研究在传统方法的基础上引入恒流源,提出电催化金属辅助化学刻蚀法,高效制备了硅纳米线/多孔硅复合结构.在外加30 mA恒定电流的条件下,硅纳米线的平均制备速率可达308 n...