铁电薄膜的制备及应用技术研究

研究出具有特色的制备铁电薄膜的 sol-gel技术;制备出高质量、高可靠的 PLT、PZT、PYZT、BST”l、PbTiO3、BaTiO3、Bi4Ti3O12多晶铁电薄膜,PLT、PZT和伽里O3异质外延生长铁电薄膜;研制出铁电薄膜热释电单元红外传感器,8元、9元、1O元线列和8X8元阵列;研制出热释电火情探测器和热释电非接触式温度测试仪。     

Sputtering preparation of ferroelectric PLZT thin films and their optical applications

Preparation of epitaxial PLZT thin films on sapphire has been investigated, and excellent ferroelectric properties such as piezoelectricity and electrooptic effect with high transparency were obtained in thin films. Moreover, a preparation process was developed involving the multitarget sputtering method, and strict control of film composition and epitaxial growth with the buffer layer of graded composition were performed. Using these PLZT thin films, some optical applications, including an acoustooptic deflector and an electrooptic guided-light switch, are shown.     

磁控溅射沉积Cu-W薄膜的特征及热处理的影响

采用磁控共溅射法制备含钨1.51%~14.20%(原子分数,下同)的Cu-W合金薄膜,并用EDX、XRD、SEM、显微硬度仪和电阻仪研究了其成分、结构及性能。结果表明,添加W可显著细化Cu-W薄膜基体相晶粒,晶粒尺寸随W含量的增加而减小,Cu-W薄膜呈纳米晶结构。Cu-W薄膜中存在W在Cu中形成的fcc Cu(W)非平衡亚稳过饱和固溶体,固溶度随W含量的增加而提高,最大值为10.65%。与纯Cu膜对比发现,薄膜的显微硬度和电阻率总体上随W含量的增加而显著增大。经200℃、400℃及650℃热处理1h后,Cu-W薄膜基体相晶粒长大,EDX分析显示晶界处出现富W第二相;薄膜显微硬度降低,电阻率下降,降幅与退火温度呈正相关。添加W引起的晶粒细化效应以及退火中基体相晶粒度增大分别是Cu-W薄膜微观结构和性能形成及演变的主要原因。     

磁控溅射Cu-Nb和Cu-Mo薄膜结构与性能

采用磁控溅射制备含1.16%～15.8%(原子分数)Nb的Cu-Nb及含2.2%～27.8%Mo的Cu-Mo合金薄膜,井采用EDX、XRD、SEM、显微硬度仪和电阻计对薄膜的成分、结构和性能进行研究。结果表明,Nb和Mo的添加分别使Cu-Nb及Cu-Mo薄膜晶粒显著细化,Cu-Nb和Cu-Mo薄膜呈纳米晶结构,存在Nb在Cu中的fcc Cu(Nb)和Mo在Cu中的fcc Cu(Mo)非平衡亚稳过饱和固溶体,固溶度随Nb或Mo含量增加而上升。添加Nb和Mo显著提高Cu-Nb及Cu-Mo薄膜的显微硬度和电阻率,且随Nb或Mo含量增加而升高。经650℃热处理1h后,Cu-Nb和Cu-Mo薄膜显微硬度和电阻率均下降,且分析表明均发生基体相晶粒长大,并出现微米-亚微米级富Cu第二相,Cu-Nb及Cu-Mo薄膜结构和性能形成及演变的主要原因是添加的Nb、Mo引起的晶粒细化效应以及退火中基体相晶粒度的增大。     

Preparation and characterization of ZnS thin films by the chemical bath deposition method

ZnS thin films prepared on quartz substrates by the chemical bath deposition (CBD) method with three type temperature profile processes have been investigated by X-ray diffraction, scanning electron microscope, energy dispersive X-ray analysis and light transmission. One is a 1-step growth process, and the other is 2-steps growth and self-catalyst growth processes. The surface morphology of CBD-ZnS thin films prepared by the CBD method with the self-catalyst growth process is flat and smooth compared with that prepared by the 1-step and 2-steps growth processes. The self-catalyst growth process in order to prepare the particles of ZnS as initial nucleus layer was useful for improvement in crystallinity of ZnS thin films prepared by CBD. ZnS thin films prepared by CBD method with self-catalyst growth process can be expected for improvement in the conversion efficiency of Cu(InGa)Se₂-based thin film solar cells by using it for the buffer layer.     

TES用超导薄膜制备及特性研究

超导转变边沿传感器(TES)是光强单位坎[德拉]量子化所需的单光子探测器,金属超导薄膜物理特性的研究是TES研究的基础.采用不同电源功率磁控溅射制备高纯Al、Ti超导纳米薄膜,分析其薄膜生长速率随气压和功率的变化.利用表面应力仪及电学测量仪,分析薄膜表面应力及电学特征.最后将薄膜放入商用稀释制冷机中,进行超低温测试,获...     

TiNi shape memory alloy coated with tungsten: a novel approach for biomedical applications

This study explores the use of DC magnetron sputtering tungsten thin films for surface modification of TiNi shape memory alloy (SMA) targeting for biomedical applications. SEM, AFM and automatic contact angle meter instrument were used to determine the surface characteristics of the tungsten thin films. The hardness of the TiNi SMA with and without tungsten thin films was measured by nanoindentation tests. It is demonstrated that the tungsten thin films deposited at different magnetron sputtering conditions are characterized by a columnar microstructure and exhibit different surface morphology and roughness. The hardness of the TiNi SMA was improved significantly by tungsten thin films. The ion release, hemolysis rate, cell adhesion and cell proliferation have been investigated by inductively coupled plasma atomic emission spectrometry, CCK-8 assay and alkaline phosphatase activity test. The experimental findings indicate that TiNi SMA coated with tungsten thin film shows a substantial reduction in the release of nickel. Therefore, it has a better in vitro biocompatibility, in particular, reduced hemolysis rate, enhanced cell adhesion and differentiation due to the hydrophilic properties of the tungsten films.     

磁控溅射制备ITO薄膜光电性能的研究

采用直流磁控溅射方法在玻璃基底上制备了ITO薄膜.分别用分光光度计和四探针仪测试了所制备ITO薄膜在可见光区域内的透过率和电阻率,研究了溅射气压、氧氩流量比和溅射功率三个工艺参数对ITO薄膜光电性能的影响.研究结果表明,制备ITO薄膜的最佳工艺参数为:溅射气压0.6 Pa,氧氩流量比1:40,溅射功率108 W.采用此工艺参数制备的ITO薄膜在可见光区平均透过率为81.18％,薄膜电阻率为8.9197×10-3Ω·cm.     

A low‐cost and reliable optical inspection system for rapid surface roughness measurements of polycrystalline thin films

Excimer laser crystallization is a well‐known industrially used technique to produce high‐performance polycrystalline silicon thin films on the commercially available inexpensive glass substrates for the development of high‐performance low temperature polycrystalline silicon thin‐film transistors in active matrix flat panel displays. A rapid optical measurement system for rapid surface roughness measurement of polycrystalline silicon thin films was developed in this study. Two kinds of thicknesses of polycrystalline silicon thin films were used to study rapid surface roughness measurements. Six different incident angles were employed for measuring surface roughness of polycrystalline silicon thin films. The results reveal that the incident angle of 20° was found to be a good candidate for measuring surface roughness of polycrystalline silicon thin films. Surface roughness (y) of polycrystalline silicon thin films can be determined rapidly from the average value of reflected direct current voltage (x) measured by the optical system developed using the trend equation of y = –8.9854x + 91.496. The maximum measurement error rate of the optical measurement system developed was less than 5.72%. The savings in measurement time was up to 83%.     

Preparation of (001)-oriented Pb(Zr,Ti)O3 thin films and their piezoelectric applications

Preparation of (001)-oriented Pb(Zr,Ti)O(3) (PZT) thin films and their applications to a sensor and actuators were investigated. These thin films, which have a composition close to the morphotropic phase boundary, were epitaxially grown on (100)MgO single-crystal substrates by RF magnetron sputtering. These (001)-oriented PZT thin films could be obtained on various kinds of substrates, such as glass and Si, by introducing (100)-oriented MgO buffer layers. In addition, the (001) oriented PZT thin films could be obtained on Si substrates without buffer layers by optimizing the sputtering conditions. All of these thin films showed excellent piezoelectric properties without the need for poling treatment. The PZT thin films on the MgO substrates had a high piezoelectric coefficient, d(31), of -100 pm/V, and an extremely low relative dielectric constant, epsilon(r), of 240. The PZT thin films on Si substrate had a very high d(31) of -150 pm/V and an epsilon(r) = 700. These PZT thin films were applied to an angular rate sensor with a tuning fork in a car navigation system, to a dual-stage actuator for positioning the magnetic head of a high-density hard disk drive, and to an actuator for an inkjet printer head for industrial on-demand printers.     

Electrochemical characterization of carbon nanotube forests grown on copper foil using transition metal catalysts

Growth of vertical, multiwalled carbon nanotubes (CNTs) on bulk copper foil substrates can be achieved by sputtering either Ni or Inconel thin films on Cu substrates followed by thermal chemical vapor deposition using a xylene and ferrocene mixture. During CVD growth, Fe nanoparticles from the ferrocene act as a vapor phase delivered catalyst in addition to the transition metal thin film, which breaks up into islands. Both the thin film and iron are needed for dense and uniform growth of CNTs on the copper substrates. The benefits of this relatively simple and cost effective method of directly integrating CNTs with highly conductive copper substrates are the resulting high density of nanotubes that do not require the use of additional binders and the potential for low contact resistance between the nanotubes and the substrate. This method is therefore of interest for charge storage applications such as double layer capacitors. Inconel thin films in conjunction with Fe from ferrocene appear to work better in comparison to Ni thin films in terms of CNT density and charge storage capability. We report here the power density and specific capacitance values of the double layer capacitors developed from the CNTs grown directly on copper substrates.     

Preparation of (001)-oriented Pb(Zr,Ti)O/sub 3/ thin films and their piezoelectric applications

Preparation of (001)-oriented Pb(Zr,Ti)O₃ (PZT) thin films and their applications to a sensor and actuators were investigated. These thin films, which have a composition close to the morphotropic phase boundary, were epitaxially grown on (100)MgO single-crystal substrates by RF magnetron sputtering. These (001)-oriented PZT thin films could be obtained on various kinds of substrates, such as glass and Si, by introducing (100)-oriented MgO buffer layers. In addition, the (001)-oriented PZT thin films could be obtained on Si substrates without buffer layers by optimizing the sputtering conditions. All of these thin films showed excellent piezoelectric properties without the need for poling treatment. The PZT thin films on the MgO substrates had a high piezoelectric coefficient, d₃₁, of -100 pm/V, and an extremely low relative dielectric constant, epsiv_r, of 240. The PZT thin films on Si substrate had a very high d₃₁ of -150 pm/V and an epsiv_r = 700. These PZT thin films were applied to an angular rate sensor with a tuning fork in a car navigation system, to a dual-stage actuator for positioning the magnetic head of a high-density hard disk drive, and to an actuator for an inkjet printer head for industrial on-demand printers.     

Dynamics of STO heteroepitaxial growth by pulsed laser deposition

The heteroepitaxial growth dynamics of STO thin films on (100) LaAlO₃ substrate by pulsed laser deposition has been studied. The laser energy density was found to be an important factor to determine the growth mechanics. High laser energy density is benefit to two dimensional layer-by-layer growth. Island growth prevails at low substrate temperature. STO thin films deposited at low oxygen partial pressure showed pellicular square grains. High oxygen partial pressure resulted in spherical STO grains. Step-terrace on substrate surface acts as a preferential nucleation site for adatoms, which leads to step-flow growth. STO thin films with atomic flat surface has been prepared on step-terraced substrate.     

Characterization of thin films on metals using proton- induced X-rays

The measurement of characteristic X-rays produced by proton bombardment of a solid surface is being used to provide quantitative compositional analyses of surface layers of metals. An integral X-ray yield equation was developed that quantitatively relates the experimentally measured X-ray yield to the thickness of thin films ranging from less than a monolayer to several thousand ångströms. The use of the equation is demonstrated for the growth of thin films through either vacuum evaporation or oxidation processes. The sensitivity of proton-induced X- ray emission (PIXE) for the measurement of very thin film growth kinetics is demonstrated from studies of the effect of fractional monolayer coverages of sulfur on the initial oxidation kinetics of iron. By combining PIXE with inert gas ion sputtering, quantitative composition-depth profiles of surface layers were obtained. Examples are presented for the profiling of iron samples implanted with 25 keV nickel ions and for a molten salt electrodeposited platinum coating on an Fe-5% Cr substrate.     

Morphology and growth of electrodeposited cuprous oxide under different values of direct current density

The growth of Cu₂O thin films electrodeposited by a two-electrode system with acid and alkaline electrolytes under different values of direct current (DC) densities was investigated. The microstructure of Cu₂O thin films produced in the acid electrolyte changes from a ring shape to a cubic shape with increasing DC density, and the microstructure of Cu₂O thin films produced in the alkaline electrolyte has a typical pyramid shape. The X-ray diffraction results show that Cu₂O thin films can be electrodeposited over a larger current domain than those deposited by a three-electrode system. The growth of Cu₂O thin films is examined under this domain, and the electrocrystallization process of such films is discussed taking into consideration the effect of current density on nucleation, cluster growth, and crystal growth.     

电流密度和衬底处理方式对CaMoO4薄膜电化学制备的影响

主要研究了利用恒电流电化学技术制备CaMoO4薄膜的工艺中,电流密度和衬底处理方式对薄膜制备的影响.研究发现,增大阳极氧化电流密度会加快薄膜的生长速度,但会加剧晶粒团簇生长的趋势、减弱薄膜与衬底的附着力和薄膜的均匀性;衬底的不同处理方式对薄膜晶粒的生长速度、沉积方式、均匀性等有较大的影响,在抛光衬底上薄膜的沉积速度比酸腐蚀和粗磨的衬底要快,且不易造成晶粒的团簇生长.结果表明,CaMoO4薄膜的电化学沉积,应在抛光衬底上进行;电流密度控制在0.5mA/cm2附近比较好.     

一种制备优质有机光学薄膜的新方法

提出了一种用真空蒸发和真空热压相结合的技术来制备优质有机光学薄膜的方法。用它制成的有机光学薄膜中没有任何残留有机溶剂,在放置过程中也不产生晶化,因而不会对光发生散射。在光通讯器件、有机发光、有机光存储器的制作等方面有广泛的应用前景。     

OVPD und Anwendung optischer Spektroskopiemethoden zur Wachstumskontrolle. OVPD and Applications of Optical Spectroscopic Methods to Growth Control

Organic Vapor Phase Deposition (OVPD) is a new thin film growth technique which is very suitable for deposition of uniform thin films on larger substrate areas. The polarization sensitive methods, ellipsometry and Reflectance Anisotropy Spectroscopy (RAS), have huge potential for the control of the growth in the OVPD process. The capability of ellipsometry to determine the thickness and the optical constants of OVPD deposited films was demonstrated using as example an Alq₃ film. RAS showed high potential for the detection of very thin organic anisotropic films, as exemplified for an PTCDA film.     

纳米颗粒薄膜的真空喷射沉积研究

利用真空喷射沉积技术制备厂Zn纳米颗粒薄膜，研究了工艺参数对薄膜形貌及晶体结构的影响规律，给出了颗粒尺度和外形随Ar气流量、蒸发源温度、喷嘴尺寸形状和沉积时间的变化规律，并对其机理进行了分析。     

High quality microcrystalline Si films by hydrogen dilution profile

Novel hydrogen dilution profiling (HDP) technique was developed to improve the uniformity in the growth direction of μc-Si:H thin films prepared by hot wire chemical vapor deposition (HWCVD). It was found that the high H dilution ratio reduces the incubation layer from 30 nm to less than 10 nm. A proper design of hydrogen dilution profiling improves the uniformity of crystalline content, X_c, in the growth direction and restrains the formation of micro-voids as well. As a result the compactness of μc-Si:H films with a high crystalline content is enhanced and the stability of μc-Si:H thin film against the oxygen diffusion is much improved. Meanwhile the HDP μc-Si:H films exhibit the low defect states. The high nucleation density from high hydrogen dilution at early stage is a critical parameter to improve the quality of μc-Si:H films.