高真空脉冲激光沉积CeO2（111）/Si（111）薄膜的结构与形貌研究

在高真空条件下,采用脉冲激光沉积法在Si(111)衬底上制备了高度(111)取向的CeO2薄膜。使用反射高能电子衍射仪对薄膜制备过程进行了原位监测,衍射花样为清晰条纹状,显示薄膜结晶质量较好,表面平整光滑。采用X射线衍射仪对不同衬底温度、不同激光能量制备的薄膜进行了结构表征,随着温度升高和能量增强,CeO2薄膜(111)峰逐渐增强且峰位越来越靠近标准峰位,表明CeO2薄膜的取向性变好且薄膜应力逐渐下降。通过椭偏仪对薄膜的折射率进行了表征,结果表明薄膜的光学性能强烈依赖其结晶质量,结晶质量最好的样品折射率接近单晶薄膜。使用高分辨透射电镜表征了样品的横断面,照片显示薄膜内部原子排列有序,结晶质量较好,部分区域与衬底取向略有偏差。     

氧压对脉冲激光沉积Si基ZnO薄膜性能的影响

采用脉冲激光沉积法在Si(111)基片上制备了ZnO薄膜.利用X射线衍射、光致发光、扫描电子显微镜等表征技术研究工作氧压对ZnO薄膜的结晶特性和光学性能的影响.研究结果表明,氧压的增大,有助于更多的氧原子进入晶格,有效减少薄膜中的缺陷和应力,使ZnO薄膜结构趋于完整,但是过高的氧压将严重地影响薄膜的沉积速率,加剧衬底Si的氧化,从而使薄膜的结晶质量恶化.所有的ZnO薄膜均显示出较强的紫外发光蜂,并且结晶性与发光特性有很好的一致性.     

CeO2掺杂对HfO2栅介质电学特性的影响

采用磁控共溅射的方法在p-Si(100)衬底上沉积了掺杂和不掺杂CeO2的HfO2薄膜。通过X射线光电子能谱(XPS)研究了薄膜中元素的化学计量比及结合能,制备MOS结构并对漏电流及电容等电学性能进行表征。结果表明,掺入CeO2后,整个体系的氧空位生成能增大,氧空位数目减少,漏电流较纯HfO2下降了一个数量级,满足作为高k材料的要求。     

Gd2O3-HfO2栅介质薄膜的外延制备及Ge-MOS电学特性分析

以Gd2O3-HfO2( GDH)固溶氧化物作为靶材,采用脉冲激光沉积技术(PLD)在Ge(100)衬底上制备了GDH高k栅介质外延薄膜,其外延生长方式为“cube-on-cube”,GDH薄膜与Ge(100)衬底的取向关系为(100)GDH∥(100)Ge和[110] GDH∥[110]Ge.通过反射式高能电子衍射(RHEED)技术研究了激光烧蚀能量和薄膜沉积温度对薄膜晶体结构的影响,分析了二者与薄膜的取向关系,激光烧蚀能量对薄膜取向影响更为显著.得到较优的GDH外延薄膜沉积工艺为:激光烧蚀能量为3 J·cm-2、薄膜的沉积温度为600℃.用磁控溅射制备了Au/Ti顶电极和Al背电极,其中圆形的Au/Ti电极通过掩膜方法获得,直径为50μm.采用Keithley 4200半导体测试仪对所制备Au/Ti/GDH/Ge/Al 堆栈结构的Ge-MOS原型电容器进行电学特性分析,测试条件为:I-E测试的电场强度0～6MV·cm-1,C-V测试的频率300 kHz～1 MHz,结果表明,厚度为5nm的GDH薄膜具备良好介电性能:k-28,EOT ～0.49 nm,适于22 nm及以下技术节点集成电路的应用.     

生长温度和退火气氛对ZnO:Al薄膜结构与性能的影响

采用直流磁控溅射法在玻璃衬底上制备ZnO:Al透明导电薄膜,研究生长温度和退火气氛对薄膜结构、形貌、光学和电学性能的影响。结果表明:不同温度下生长的ZnO:Al薄膜均为高度c轴取向的六角铅锌矿结构,400~900 nm波长范围内薄膜的平均透过率均超过85%。ZnO:Al薄膜的电学性能强烈依赖于生长温度,室温~500℃范围内,500℃下生长的薄膜具有最大的载流子浓度(2.294×1021 cm-3)和最低电阻率(4.095×10-4-.cm)。退火气氛对薄膜的性能影响显著,经过不同气氛退火后,薄膜的表面粗糙度降低,结晶质量和光学性能有所提高;在O2、N2、空气等气氛下退火,薄膜的载流子浓度降低,电阻率上升;Ar和真空退火时,薄膜载流子浓度上升,电阻率显著下降。     

质量分离的双离子束沉积法生长CeO2(111)/Si薄膜

利用一种全新的薄膜生长技术-质量分离的双离子束沉积技术,在较低温度(400℃)下对CeO2(111)/Si(100)薄膜的生长进行了研究.两束离子的比例以及离子束的能量对薄膜的成分和晶体质量有很大影响,较高能量(300eV)的离子束对薄膜有轰击作用,并有助于薄膜的择优取向生长.在400℃时,制备了CeO2(111)/Si(100)单晶薄膜.     

不同生长温度对Ga掺杂ZnO透明导电薄膜性能的影响

采用磁控溅射方法在普通载玻片衬底上制备了Ga掺杂的ZnO(GZO)透明导电薄膜,并研究了不同生长温度对GZO透明导电薄膜的结构性能、电学性能及光学性能的影响.制备的GZO透明导电薄膜均沿(002)方向的择优取向生长,薄膜的表面形貌为蠕虫状,表明薄膜内存在较大的残余应力.随着生长温度的升高,GZO薄膜的电阻率先减小后增大,在生长温度为250℃时,薄膜的最低电阻率为1.91×10-3 Ωcm.不同生长温度下所制备的GZO薄膜在可见光波段的平均透过率均大于90％,薄膜具有优异的光学特性.     

反应溅射法在蓝宝石衬底上制备CeO2缓冲层

用金属铈作为靶材,采用射频反应磁控溅射法在（1 102）蓝宝石衬底上制备C轴取向CeO2外延薄膜缓冲层。结果表明在温度低于450℃或溅射功率低于50 W的条件下CeO2薄膜呈（111）取向生长;升高温度和功率CeO2薄膜的（111）取向减弱,（002）取向增强;在温度高于750℃或溅射功率高于120 W条件下CeO2薄膜呈（111）取向和（002）取向混合生长。结合X射线衍射仪和原子力显微镜表征CeO2薄膜的结构和表面形貌,获得在最优化条件下（衬底温度在680℃左右,溅射功率在80 W左右,溅射气压在25 Pa,氩氧比在15∶1）制备的CeO2薄膜具有优良的面内面外取向和平整的表面。     

质量分离的双离子束沉积法生长CeO2（111）／Si薄膜

利用一种全新的薄膜生长技术-质量分离的双离子束沉积技术,在较低温度（400℃）下对CeO2(111)/Si(100)薄膜的生长进行了研究,两束离子的比例以及离子束的能量对薄膜的成分和晶体质量有很大影响。较高能量（300eV)的离子束对薄膜有轰击作用,并有助于薄膜的择优取向生长,在400℃时,制备了CeO2(111)/Si(100)单晶薄膜。     

Si衬底上3C-SiC异质外延应力的消除

利用低压化学气相沉积方法在N型Si衬底上异质外延生长3C-SiC薄膜,研究和分析了不同碳化工艺和生长工艺对3C-SiC外延层的影响;探讨了Si衬底3C-SiC异质外延应力的消除机理.通过台阶仪和XRD对不同工艺条件下的外延层质量进行分析,得到最佳工艺条件的碳化温度为1000 ℃,碳化时间为5 min,生长温度为1200 ℃,生长速度为4 μm/h.对最佳工艺条件下得到的外延层的台阶仪分析表明外延层弯曲度仅为5μm/45 mm;而外延层的XRD和AFM分析表明,3 μm厚度外延层SiC(111)半高宽为0.15°,表面粗糙度为15.4nm,表明外延层结晶质量良好.     

Synthesis and characterization of Sb-doped SnO2-（CeO2-TiO2） composite thin films deposited on glass substrates for antistatic electricity and UV-shielding

Sb-doped SnO2(ATO)-(CeO2-TiO2) thin Films were deposited on glass substrates using the mixed solution including CeO2-TiO2 precursor and ATO particles by sol-gel dip coating process.ATO particles were prepared using low-temperature hydrothermal process.The mixed molar ratio of ATO to(CeO2-TiO2) vs the properties of CeO2-TiO2 thin film was investigated.The optical properties of the films were characterized by UV-visible transmission and infrared reflection spectra,the sheet resistance of ATO particles and films were measured by rubber sheeter(MYI-50) and four-point probe(HisuperGroup Inc,SDY-5),the surface morphology and structure of the films were analyzed using 3D Digitale Mikroskop and X-ray diffraction(XRD),respectively.The results showed that the ATO precursor solution lost weight completely at about 500 oC,and the ATO particles was obtained,which indicated the same rutile lattice structure as SnO2.The glass substrates coated with ATO-(CeO2-TiO2) thin films showed better properties in antistatic electricity(104-106 Ω/),shielding UV(almost 100%),visible light transmission(70%) and infrared reflection(>30%).     

Ultraviolet-shielding and conductive double functional films coated on glass substrates by sol-gel process

Ultraviolet-shielding and conductive double functional films were composed of CeO2-TiO2 film and SnO2:Sb film deposited on glass substrates using sol-gel process.Ce(NO3)3·6H2O and Ti(C4H9O4),SnCl4 and SbCl3 were used as precursors of the two different functional films respectively.The CeO2-TiO2 films were deposited on glass substrates by sol-gel dip coating method,and then the SnO2:Sb films with different thickness were deposited on the pre-coated CeO2-TiO2 thin film glass substrates,finally,the substrates coated with double functional films were annealed at different temperatures.The optical and electrical properties of the CeO2-TiO2 films and the double films were measured by UV-Vis spectrometer and four probe resistance measuring instrument.The crystal structures and surface morphology of the films were characterized using XRD and optical microscope,respectively.The obtained results show that the ultraviolet-shielding rate of the glass substrates with CeO2-TiO2 films is not less than 90%,and transmittance in visible lights can reach 65%.With the thickness of the SnO2:Sb film increasing,its conductivity became better,and the surface resistance is about 260 Ω/ when the SnO2:Sb films were deposited 11 cycles of the dip on the pre-coated CeO2-TiO2 glass.The ultraviolet-shielding rate of the glass substrates with double functional films is higher than 97%,and the peak transmittance in the visible lights is 72%.Additionally,with increasing the heat treatment time,the Na+ of the glass substrates diffuses into the films,resulting in the particle size of SnO2 crystal smaller.     

Electrocatalytic enhancement of methanol oxidation by adding CeO2 nanoparticle on porous electrode

The polyaniline/polysulfone(PAN/PSF) composite films were prepared by electropolymerization,and then CeO2-Pt particles were codeposited into this composite film to obtain the CeO2-Pt-modified polyaniline/polysulfone(CeO2-Pt/PAN/PSF) electrodes.Their morphol-ogy and chemical component were characterized by field emission scanning electron microscopy(FESEM) and energy dispersive X-ray spectroscopy(EDS),respectively.The results showed that the composite film had bi-layer structure with asymmetrical pores,and platinum and cerium oxide particles were homogeneously dispersed in the modified film electrodes.The cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) techniques were applied to investigate the electrocatalytic activity of the Pt-CeO2/PAN/PSF electrodes.It was indicated that appropriate amount of CeO2 could enhance the catalytic activity of Pt for methanol electro-oxidation.Chronoamperometry(i-t) measurements revealed that the Pt-CeO2/PAN/PSF electrode was relatively endurable for intermediate production.In addition,different mix-ing amounts of Pt and CeO2 nanoparticles were also investigated in detail.     

Influence of Nanometric Ceria Sol-gel Coating on Oxidation Behavior of Chromium at 1000℃

 Isothermal oxidation behavior of chromium with and without nanometric sol-gel CeO2 coating is studied at 1000℃ in air. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to examine the surface morphology and microstructure of their oxide films. It is found that ceria coating greatly improves the anti-oxidation property of chromium. Laser Raman spectrometer and X-ray diffraction spectrometer (XRD) are also used to study the stress level in oxide films formed on ceria-coated and ceria-free Cr. Secondary ion massive spectrum (SIMS) is used to examine Cr, O and Ce element distribution in depth in oxide films. Results show that nano-ceria application greatly reduces the growing speed and grain size of Cr2O3 film, and his fine grain-sized Cr2O3 film probably has better high temperature plasticity, i.e. oxide film relieves part of the compressive stress by means of creeping. Meanwhile, CeO2 changes the oxide film growing mechanism from predominant cation outward diffusion to anion inward diffusion. XRD and Raman testing results both show the stress declination effect due to nano-CeO2 application, and their discrepancy is analyzed concerning to the rare earth effect.     

Optical and Micro-Structural Properties of ZnO Thin Films Grown on Silicon Substrate by Pulsed Laser Deposition

ZnO thin films were deposited on n-Si (111) at various substrate temperatures and oxygen pressures by pulsed laser deposition (PLD) using a Nd∶YAG laser with the wavelength of 1064 nm. X-ray diffraction (XRD), photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the microstructure, optical property and morphology of the ZnO thin films. A comparatively optimal crystallized ZnO thin film was obtained at the substrate temperature of 600 ℃ in oxygen pressure of 50 mTorr. The intensity of the luminescence strongly depends on the stoichiometry of the film as well as the crystalline quality.     

稀土-硼共渗预处理对YG6表面金刚石薄膜质量的影响

分别对YG6(WC-wt.6%.Co)硬质合金基体表面进行常规固态渗硼和固态稀土(CeO2)共渗处理,再以甲烷和氢气为反应气体,采用热丝化学气相沉积法在合金基体表面沉积金刚石膜,通过调控灯丝功率和进气总流量制备微米晶或纳米晶金刚石膜。利用场发射扫描电镜、X射线衍射仪、激光拉曼光谱仪和洛氏硬度计对渗硼基体和金刚石膜进行检测分析,研究YG6硬质合金基体稀土硼共渗与常规固态渗硼处理对微米晶金刚石膜与纳米晶金刚石膜的物相组成、结构形貌和附着性能的影响。结果表明,与常规固态渗硼处理相比,稀土(CeO2)硼共渗样品表面残留物较少,沉积的金刚石膜样品表面粗糙度低,在1 000 N载荷下薄膜无剥落现象,表现出较好的附着性能;纳米晶金刚石膜的生长速率低于微米晶金刚石膜,但其附着性能明显优于微米晶金刚石膜。     

What is the Effect of Critical Surface Tension of PbSO3 Thin Film?

This study focuses on the critical surface tension of lead sulfite (PbSO₃) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO₃ thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO₃ thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.     

Effect of humidity on microstructure and properties of YBCO film prepared by TFA-MOD method

Epitaxial YBCO superconducting films were deposited on the single crystal LaAlO3. (001) substrate by metal organic deposition method. All YBCO films were fired at 820 ℃ in humidity range of 2.6%-19.7% atmosphere. Microstructure of YBCO thin films was ana-lyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Superconducting properties of YBCO films were measured by four-probe method. XRD results showed that the second phase (such as BaF2)and a-axis-oriented grains existed in the films prepared at 2.6% humidity condition; a-axis-oriented grains increased in the film prepared at higher than 4.2% humidity condition; almost pure c-axias-oriented grains existed in the films fired at 4.2% humidity condition. Morphologies of the YBCO films showed that all films had a smooth and crack-free surface. YBCO film prepared at 4.2% humidity condition showed Jc value of 3.3 MA/cm2 at 77 K in self-field.     

Structural, electrical and surface morphological studies of Cd2SnO4 and Mg doped Cd2SnO4 thin films

The technologically important conductive Cadmium stannate (Cd₂SnO₄) and Magnesium doped cadmium stannate (Cd₂SnO₄: Mg) thin films were prepared using Cadmium acetate and stannous chloride by spray pyrolysis technique. Films prepared are crystalline and have cubic CdO phase with SnO₂. The X-ray diffraction patterns of both thin films shows perfect crystalline structure and from the data, the particle diameter of both films were calculated. Atomic Force Microscopy (AFM) of both films reveals the uniform thickness of the films and the presence of uniform grain growth in Cd₂SnO₄ and Mg doped Cd₂SnO₄ thin films. Thickness of Cadmium stannate film is 725nm and that of Magnesium doped Cadmium stannate film is 285nm. The indirect band gap energy of Cd₂SnO₄ film is 2.71eV and for magnesium doped Cd₂SnO₄ is 2.97eV were observed from the UV-Visible absorption spectrum studies. Presence of uniform grain growth is found in both thin films. The doping of Magnesium in Cadmium stannate film improves the electrical properties without affecting its structural properties.