热蒸发制备CdSe薄膜的退火工艺研究

采用真空热蒸发技术在光学玻璃基底上制备了CdSe薄膜,研究了真空下不同退火温度和退火时间对CdSe薄膜晶体结构和表面形貌的影响。XRD结果表明,在400~500℃范围下退火2h、5h的CdSe薄膜晶型不发生改变,结晶性随退火温度升高而增强,其晶粒尺寸从32nm增加至50nm。SEM结果表明,在450℃下退火2h后的CdSe薄膜表面颗粒分布均匀且排列规则、无裂纹。AFM结果表明,在450℃下退火2h后的CdSe薄膜致密性好,表面粗糙度低(5.19nm)。因此采用真空热蒸发制备的CdSe薄膜的热处理条件确定为:退火温度450℃,退火时间2h。     

快速热处理对(Ba,Sr)TiO3薄膜晶化行为的影响

采用射频溅射法在Si(111)基片上制备了(Ba,Sr)TiO3(BST)薄膜,并对制备的薄膜进行了快速退火热处理.采用X射线衍射和原子力显微镜分析了退火温度、退火时间和加热速度对BST薄膜晶化行为的影响.研究结果表明,BST薄膜的晶化行为强烈依赖于退火温度、退火时间和加热速度.BST薄膜的结晶度随退火温度的升高而提高.适当的热处理可降低BST薄膜的表面粗糙度,BST薄膜的表面粗糙度随退火温度的升高经历了一个先降低后增大的过程,但退火后BST薄膜的表面粗糙度都小于制备态薄膜的表面粗糙度.BST薄膜的晶粒尺寸随退火温度的升高经历了一个先增大后减小的过程.随退火时间的延长,BST薄膜的特征衍射峰越来越强,薄膜的晶化程度越来越高.随退火时问的延长,BST薄膜的晶粒尺寸和表面粗糙度也经历了一个先增大后减小的过程.BST薄膜的晶粒大小主要由退火温度决定.高的升温速率可获得较小的晶粒.     

后退火对射频磁控溅射法制备Mg掺杂Ga_2O_3薄膜性质的影响

本文采用双靶材交替溅射的射频磁控溅射法生长了高质量的Mg掺杂氧化镓薄膜,并将制备的样品在1000℃条件下进行后退火处理,以研究退火前后Mg掺杂Ga_2O_3薄膜的性质变化。XRD结果表明,退火后的(004)、(■)和(120)峰从无到有,(401)、(■)和(■)峰由强变弱,表明退火改变了Mg掺杂Ga_2O_3薄膜的结构。AFM结果表明,退火后的薄膜表面均方根粗糙度由1.3637nm增大到17.1133nm。EDS结果表明,退火处理后的Mg元素重量百分比有所提高。紫外可见透射光谱研究表明,退火前薄膜在200-1500nm波长范围内的平均光透过率较低,大约为80%,退火后平均光透过率明显提高到90%以上,此外薄膜光学吸收边蓝移,带隙宽度变大,表明退火有助于改善薄膜结构,增强光透性。光致发光谱实验结果表明,相比较退火处理后的薄膜,退火前的光致发光峰几乎可以忽略不计,这说明退火可显著改变Mg掺杂Ga_2O_3薄膜的光致发光特性。     

原位退火处理对ZnS/Si薄膜结晶性能的影响

采用脉冲激光沉积法在Si衬底上生长出厚度为400nm的一系列ZnS薄膜,进行原位退火处理,获得单晶结构的闪锌矿型ZnS薄膜。首次报道了采用原位退火处理后获得单晶ZnS薄膜为立方结构的闪锌矿且薄膜沿(111)晶面择优生长,同时研究了其结晶质量与退火工艺之间的关系。结果显示随着退火温度的升高,薄膜的平均晶粒尺寸由200℃的13.357nm增长到400℃的27.232nm,另外薄膜的平均粗糙度由2.05nm下降达到1.14nm。采用脉冲激光沉积法制备的ZnS薄膜在400℃退火后表现出极好的单晶择优取向生长以及良好的表面平整度,为研究单晶ZnS薄膜提供一种实验解决思路。     

电子束蒸发法制备掺钇稳定氧化锆薄膜的光学特性研究

利用电子束蒸镀方法在单晶硅和石英玻璃上制备了掺不同Y_2O_3浓度的掺钇稳定ZrO_2薄膜(YSZ),用X射线衍射、原子力显微镜、扫描电子显微镜和透射光谱测定薄膜的结构、表面特性和光学性能,研究了退火对薄膜结构和光学性能的影响.结果表明:一定浓度的Y_2O_3掺杂可以使ZrO_2薄膜稳定在四方相,退火显著影响薄膜结构,随着温度的升高薄膜结构依次经历由非晶到四方相再到四方和单斜混合相转变;AFM分析显示薄膜表面YSZ颗粒随着退火温度的升高逐渐增大,表面粗糙度相应增大,晶粒大小计算表明,退火温度的提高有助于薄膜的结晶化,退火温度从400℃到1100℃变化范围内晶粒大小从15.6nm增大到46.3nm;同时利用纳秒激光对薄膜进行了破坏阈值测量,结果表明电子束蒸镀制备YSZ薄膜是一种制备高抗激光损伤镀层的有效方法.     

多晶硅薄膜的铝诱导晶化法制备及其晶粒的择优取向特性

采用铝诱导非晶硅薄膜晶化技术制备了多晶硅薄膜,并研究了多晶硅的成核和生长特性。非晶硅薄膜采用等离子体增强化学气相沉积法制备,其表面沉积铝薄膜后经不同温度的氮氛围退火处理。结果表明,退火后的硅薄膜层与铝层发生置换,所生长的多晶硅颗粒的平均尺寸约为150nm。X射线衍射分析结果揭示,薄膜的晶向显著依赖于退火温度,较低温度下,铝诱导晶化速率较慢,薄膜的优化晶向与非晶硅薄膜中团簇的初始原子排列趋势紧密相关。而较高温度下,铝诱导晶化促使多晶硅(111)择优成核及随后的固相生长。     

快速热处理对BaSrTiO3薄膜微结构的影响

采用射频溅射法在Si基片上制备BaSrTiO3(BST)薄膜,利用X射线衍射和原子力显微镜(AFM)研究了快速热处理温度和时间对BaSrTiO3薄膜微结构的影响.结果表明:BST薄膜的衍射峰强度和结晶度随退火温度的升高而提高.随退火温度的升高,BST薄膜的表面粗糙度经历先降低后增大的过程,而BST薄膜的晶粒尺寸单调减小.当退火温度为700℃时,随退火时间的增加,BST薄膜的晶粒尺寸几乎不发生变化,而表面粗糙度单调减小.     

退火对硼掺杂微晶硅薄膜性能的影响

采用射频等离子体增强化学气相沉积(RFPECVD)法制备了不同硼烷掺杂比例的微晶硅薄膜.随后在不同温度、不同气氛下,对沉积得到的P型微晶硅薄膜进行了退火处理.研究发现,对初始晶化率较高的薄膜,退火后其晶化率发生下降;初始晶化率较低的薄膜,退火后其晶化率则有所提高;并且,在高真空中退火更有利于薄膜的晶化.退火后,薄膜表面...     

后退火对射频磁控溅射制备β-Ga_2O_3薄膜的影响

采用射频磁控溅射法制备了氧化镓(Ga_2O_3)薄膜,计算了薄膜的O/Ga摩尔比,比值为1.57。研究了后退火对薄膜结构,形貌特征和光学带隙的影响。X射线衍射(XRD)结果表明,退火前的Ga_2O_3薄膜是一种无定形结构。在600℃氧气氛中退火2h后,薄膜开始出现β-Ga_2O_3的(■01)衍射峰;随着退火温度的升高,β-Ga_2O_3(■01)衍射峰进一步增强,并且半高宽从0.61°减小到0.49°。原子力显微镜(AFM)测试结果表明,退火前后薄膜表面的均方根粗糙度从3.47 nm增加到了7.08 nm,晶粒尺寸从19 nm增加到了53 nm。紫外-可见分光光度计(UV-VIS)测试结果表明Ga_2O_3薄膜在250 nm-1500 nm波长范围内的平均透过率在85%以上。利用Tauc公式计算了Ga_2O_3薄膜的光学带隙,带隙宽度在(4.85-5.06)eV之间,且随退火温度增加而减小。分析了表面形貌、光学带隙与薄膜结构之间的关系。     

退火处理对溶胶-凝胶法制备AZO薄膜性能的影响

采用溶胶-凝胶旋涂法在普通载玻片衬底上制备出Al3 掺杂ZnO(AZO)薄膜.对所制备的薄膜在空气气氛中进行了不同温度(400～600℃)的退火处理,并在500℃下的不同气氛(氢气和氩气)中进行退火处理.利用XRD和SEM等分析手段对薄膜进行了表征,测定了薄膜的透光性.研究表明,随空气中退火温度的提高,ZnO薄膜(002)衍射峰强度得到增强,半高宽逐渐减小,透射率从85%提高到95%.薄膜晶粒尺寸范围为23.50～29.80 nm;在氢气和氩气气氛下退火得到的薄膜性能均优于在空气中退火得到的薄膜性能.     

TiO2--Ta2O5 composite thin films deposited by radio frequency ion-beam sputtering

TiO2--Ta2O5 composite films were prepared by a radio frequency ion-beam sputtering deposition process, and the refractive indices and extinction coefficients of the composite films were found to be between those of the TiO2 and Ta2O5 films. The structure of the as-deposited films was amorphous, and the surface roughness was approximately 0.1 nm. The residual stress of the composite films was less than that of pure TiO2 film. The structure of the composite films after annealing was amorphous, with low surface roughness and slightly increased residual stress. The film containing 6.3% TiO2 displayed better properties than either the pure TiO2 or the pure Ta2O5 film.     

Ta2O5-Incorporated WO3 nanocomposite film for improved electrochromic performance in an acidic condition

We report electrochromic and electrochemical properties of a WO3-Ta2O5 nanocomposite electrode that was fabricated from co-sputtering. Transmission electron microscopy (TEM) images of the WO3-Ta20 nanocomposite electrode revealed that morphology of the WO3 film was changed by incorporation of Ta2O5 nanoparticles, and their chemical states were confirmed to be W6+ and Ta5+ oxides from X-ray photoelectron spectroscopy (XPS). The introduction of Ta2O5 to the WO3 film played a role in alleviating surface roughness increase during continuous potential cycling; whereas the surface roughness of the WO3 film was increased from ca. 3.0 nm to ca. 13.4 nm after 400 cycles, the roughness increase on the WO3-Ta2O5 was significantly reduced to 4.2 nm after 400 cycles, as investigated by atomic force microscopy (AFM). This improvement of the stability by adding Ta2O5 may be responsible for the enhanced electrochemical and optical properties over long-term cycling with the WO3-Ta2O5 nanocomposite electrode.     

Broadband NIR emission in sol-gel Er(3+)-activated SiO2-Ta2O5 glass ceramic planar and channel waveguides for optical application

An Er(3+)-doped SiO2:Ta2O5 optical channel waveguide and nanocomposite were prepared by the sol-gel route at a Si:Ta 50:50 molar ratio. Channels with an excellent surface profile were easily and quickly fabricated by focusing a femtosecond laser onto the surface of multilayered films deposited on SiO2/Si substrates. In parallel, the same sol used to prepare the film was annealed at 900, 1000, and 1100 degrees C for 2 h, to get the nanocomposite materials. A broadband NIR emission around 1538 nm, assigned to the 4I13/2 --> 4I15/2 transition of the Er3+ ions was observed in the nanocomposites of amorphous SiO2 containing dispersed Ta2O5 nanocrystals. The 4I13/2 lifetime and emission bandwidth depend on the annealing temperature. In conclusion, Er(3+)-doped SiO2:Ta2O5 channel waveguides and nanocomposites are promising materials for photonic applications.     

电绝缘用ta-C薄膜的微观结构与电学特性

采用ta—C薄膜用于SOI结构中的绝缘层，在高温高功率器件中有很大的应用潜力。应用真空磁过滤弧源沉积(FAD)的方法制备了ta—C薄膜。通过AFM、non—RBS、IR、I—V、C—V等方法对薄膜的表面形貌、微观结构和电学性能进行了研究。研究表明，ta—C薄膜的sp^3键含量高达87％，且具有很高的表面光洁度(粗糙度低于0．5nm)及较好的电绝缘性能，击穿场强达到4．7MV／cm。     

磁控反应溅射制备的Ta2O5薄膜的光学与介电性能

采用直流磁控反应溅射技术，在不同的Ar/O2比条件下制备了系列Ta2O5薄膜样品，采用紫外．可见光透射光谱和椭偏光谱测试分析技术，研究了Ta2O5薄膜在可见光范围内的透射率、折射率和消光系数；同时还采用HP 4192A阻抗分析仪测试分析了样品在500Hz～13MHz频段的介电谱，结果表明在300～700nm的可见光波长范围内，氧化钽薄膜的消光系数k→0，折射率＞2．0，透射率大约80％。500Hz下的低频介电常数5的典型值为20.1。损耗角正切tgδ为19.9。     

Controlling the crystallinity and roughness of atomic layer deposited titanium dioxide films

The surface roughness of thin films is an important parameter related to the sticking behaviour of surfaces in the manufacturing of microelectomechanical systems (MEMS). In this work, TiO2 films made by atomic layer deposition (ALD) with the TiCl4-H2O process were characterized for their growth, roughness and crystallinity as function of deposition temperature (110-300 degrees C), film thickness (up to approximately 100 nm) and substrate (thermal SiO2, RCA-cleaned Si, Al2O3). TiO2 films got rougher with increasing film thickness and to some extent with increasing deposition temperature. The substrate drastically influenced the crystallization behaviour of the film: for films of about 20 nm thickness, on thermal SiO2 and RCA-cleaned Si, anatase TiO2 crystal diameter was about 40 nm, while on Al2O3 surface the diameter was about a micrometer. The roughness could be controlled from 0.2 nm up to several nanometers, which makes the TiO2 films candidates for adhesion engineering in MEMS.     

Topographic measurements of supersmooth dielectric films made with a mechanical profiler and a scanning force microscope

The roughnesses of five supersmooth dielectric films of Si(3)N(4), TiO(2), HfO(2), Ta(2)O(5), and Al(2)O(3) prepared by an ion-beam-sputtering technique were measured with a commercial Talystep mechanical profiler and a sensitive Leica WYKO SPM30 scanning force microscope (SFM) to determine how much roughness the films added to the ～1-?-rms roughness fused-silica substrates on which they were deposited. In all cases the increase in roughness for the three-quarter-wave optical thickness films was a small fraction of an angstrom. SFM measurements showed that the topography of the Ta(2)O(5) and Al(2)O(3) films was less random than that of the other film materials and the substrates.     

Electrochemical fabrication of nanodimensional multilayer films

A novel method of fabricating nanodimensional multilayer films using electrochemistry is described. A thin layer of tantalum (Ta) is sputtered on a smooth insulating substrate. Ta is partially electrochemically oxidized (anodized) forming a Ta(2)O(5) layer. The rate of Ta consumption, the rate of Ta(2)O(5) expansion, and the dependence of Ta(2)O(5) thickness on anodization conditions have been carefully characterized to enable accurate predictions of the resulting thicknesses of both layers. Due to strong planarization action of the anodization process, the resulting interfaces Ta/Ta(2)O(5) and Ta(2)O(5)/electrolyte are remarkably smooth. The next layer of Ta is deposited on top of Ta(2)O(5), and the process is repeated as many times as needed. The Ta(2)O(5) layers are amorphous and pinhole free. We report fabrication of 10-layer structures with pitches ranging from 200 nm down to 12 nm and with excellent uniformity between the layers. The smallest achieved thickness of Ta layers is only 2.8 +/- 0.1 nm. The edges of such films, after proper polishing and etching, could serve as templates in nanoimprint lithography and in other applications.     

Characterization of TiO2/Ta2O5 Films Synthesized by Ion Beam on NiTi Alloy for Biomedical Applications

The biocompatibility of implants is determined by their corrosion resistance and surface characteristics. In this study, the surface composition, morphology and microstructure of TiO2/Ta2O5 films synthesized by ion beam enhanced deposition on NiTi alloy were studied. The scratch test results indicate that the interface adhesive strength of TiO2/Ta2O5 film increases with the increasing Ta content. The electrochemical corrosion measurement shows that the TiO2-36%Ta2O5 film is optimal for improving corrosion resistance of NiTi alloy.     

Nanogranular L1(0) FePt-C-Ta2O5 composite media for perpendicular recording applications

In this report, the effect of simultaneously adding two dopants (C and Ta2O5) in FePt was investigated. (Fe55Pt45)79C21-(x vol%) Ta2O5 films (where x = 0% to 20%) were prepared using both low and high power magnetron sputtering on MgO (2 nm)/CrRu (30 nm) underlayers with in-situ heating at 350 degrees C. Films deposited at low power showed a decrease in exchange coupling with increasing Ta2O5 content. Out-of-plane coercivity of 7.2 kOe was observed even with up to 20 vol% Ta2O5. X-Ray diffraction spectra showed presence of FePt(001) texture for all compositions of Ta2O5 ranging from 0 to 20 vol% suggesting that the perpendicular anisotropy was maintained even with up to 20 vol% of dopant content. Films deposited at high power showed a different behavior with an initial increase in out-of-plane coercivity to 8.2 kOe and a reduction in exchange coupling with loop slope parameter (alpha) approaching a fully decoupled value of 1. Further increase in doping content led to deterioration in the out-of-plane coercivity, as well as an increase in the exchange coupling.