不同温度制备氟化镱薄膜的工艺研究

利用电子束蒸发在硅基底材料上沉积氟化镱(YbF3)薄膜,并对不同沉积温度所得薄膜进行了研究。研究结果表明,在反可见透红外波段上,沉积温度对于YbF3薄膜的物理和光学特性有较大影响。当沉积温度为150℃和180℃时,硅基底上的YbF3薄膜的光学性能和可靠性较差;当沉积温度为220℃和240℃时,硅基底上的YbF3薄膜具有良好的光学性能和可靠性,能适用于不同要求的薄膜产品研制。     

真空热处理对硫化锌薄膜光学与微结构特性的影响

针对电子束蒸发离子辅助沉积的硫化锌薄膜,研究了550℃以下真空热处理对其光学与微结构特性的影响。薄膜光学和微结构特性的测试分析表明:制备后薄膜为类立方结构的ZnS,在337.5nm波长处出现临界特性转折点,随着热处理温度的增加,转折波长两侧的消光系数变化规律相反,折射率和物理厚度呈现下降趋势,薄膜的禁带宽度逐渐增加;在红外波段的薄膜折射率与热处理温度的变化并不显著,在350℃下热处理时消光系数出现转折,主要是由晶粒变小的趋势所致;通过晶相分析,硫化锌薄膜经历了类立方结构到六方结构的转换,与禁带宽度的变化趋势基本一致。分析结果表明,光学特性变化的根本原因是薄膜的微结构特性变化。     

无氢类金刚石薄膜的过滤式阴极电弧沉积

研制了一套过滤式阴极电弧沉积设备 ,并利用该设备成功地获得了类金刚石薄膜。扫描电镜分析表明 :获得的薄膜在硅基片上是光滑和致密的。喇曼光谱研究表明 ,这种薄膜是典型的无氢类金刚石薄膜。膜层的摩擦试验表明 :无氢类金刚石薄膜的摩擦系数较低 ,是一种理想的耐磨材料     

几种氟化物薄膜材料的光学特性

为了进一步明确氟化薄膜材料在紫外(UV)-真空紫外(VUV)波段的光学常数,研究了真空紫外领域常用的基底材料和6种大带隙的氟化物薄膜材料的光学特性.分别在熔石英(JGS1)基底和氟化镁单晶基底上用热舟蒸发法以不同的沉积速率和不同的基底温度镀制了3种高折射率材料薄膜LaF3、NdF3、GdF3和3种低折射率材料薄膜MgF2、AlF3、Na3AlF6;在国家同步辐射真空紫外实验站测定了它们120～300 nm的透射光谱曲线,用商用lambda900光谱仪测量了它们190～500 nm的透射光谱曲线,两者相结合标定了透射率的准确值.用包络法和模拟退火相结合研究了它们在120～500 nm的折射率和消光系数,给出了6种氟化物材料的光谱色散曲线.结果显示,3种高折射率薄膜的折射率在157 nm处约为1.77～1.89,而3种低折射率薄膜的折射率在157 nm处约为1.44～1.48;研究表明,选用折射率相差较大的高、低折射率氟化物薄膜,可在膜系设计中组成高低折射率材料对,用于设计各种实用的薄膜器件.     

YT15硬质合金成形铣刀的金刚石涂层制备及应用研究北大核心

针对YT15硬质合金B212型成形铣刀片,采用两种不同的化学试剂对硬质合金基体预处理,以热丝化学气相沉积的方法沉积微米级金刚石薄膜。以65%高体分SiC颗粒增强铝基复合材料为试件材料,对比考察了金刚石薄膜涂层成形铣刀与未涂层硬质合金铣刀的切削特性,从而对铣刀的涂层效果进行评价。结果表明:经预处理后的YT类硬质合金表面粗糙度较YG类减小约10%,以平行布置热丝方式和现有的沉积工艺涂覆的金刚石薄膜均匀性较好;涂覆的金刚石薄膜在铣削过程中具有良好的附着强度,且经酸碱预处理及相应的涂层工艺较适合此类材料的粗加工,醇碱预处理方法较适合其半精加工;涂层刀具持续加工后的工件表面质量优于且稳定于未涂层刀具。     

新的镀层装置

美国齐梅脱公司正在研制一种多功能的离子复合沉积装置,该装置将使离子注射和薄膜汽相沉积技术两者结合起来。用户有了该装置后,使用离子枪就能把1～4种材料注入基体中而形成所需要的表层合金。据公司说,该种装置将使难溶金属首次在所需要的部位获得合金化;也可在零件表面上首先用汽相沉积技术镀层(可多至四     

应用等离子体离子辅助技术沉积的锗基底红外减反射膜

红外光学系统大多数均采用锗作为透镜和窗口的材料,由于其折射率高达４．０,引起的反射损失较大,降低了红外光能量的透过率和红外成像系统的能力。为了减少锗表面的反射损失,我们研制了高性能的红外减反射膜,使锗透镜的红外透射率高达９８％以上。通过等离子体离子辅助沉积技术的应用,。获得了耐久性能优异的红外减反投奔膜,满足了杜瓦瓶封接钎焊工艺对窗口膜层的苛求。     

应用等离子体离子辅助技术沉积的锗基底红外减反射膜

红外光学系统大多数均采用锗作为透镜和窗口的材料,由于其折射率高达４．０,引起的反射损失较大,降低了红外光能量的透过率和红外成像系统的能力。为了减少锗表面的反射损失,我们研制了高性能的红外减反射膜,使锗透镜的红外透射率高达９８％ 以上。通过等离子体离子辅助沉积技术的应用,获得了耐久性能优异的红外减反射膜,满足了杜瓦瓶封接钎焊工艺对窗口膜层的苛求,也满足了红外热像仪系统对膜层的要求,而且所有膜层均无放射性     

脉冲多弧离子镀制备类金刚石薄膜的力学特性

利用脉冲多弧离子镀技术在硅基底上沉积类金刚石薄膜。分析了类金刚石薄膜的硬度和工艺参数的关系 ,讨论了薄膜的耐磨性和化学稳定性。     

飞秒脉冲激光沉积类金刚石膜实验研究

期望用类金刚石膜作为硅的红外保护/增透膜,采用波长为800nm,脉宽50fs,重复频率1KH z的T i:Sapph ire飞秒激光器及石墨靶材在单晶S i片上沉积了约0.7μm~1μm厚的类金刚石膜(d iam ond-like carbon film s,DLC),获得了光滑致密,硬度显著提高,红外透过率有一定增加的样品。通过对薄膜拉曼光谱和X射线光电子能谱等的测试,发现单脉冲能量在0.4m J~1.6m J范围内变动时,单脉冲能量0.8m J获得的类金刚石膜综合性能最佳,其对应的焦斑功率密度计算值为1.4×1014W/cm2。     

偏压对掺钨含氢类金刚石碳膜摩擦学性能的影响

利用非平衡磁控溅射技术在单晶硅片及9Cr18基体表面制备不同偏压下的掺钨含氢类金刚石碳膜。采用Ra-man光谱分析薄膜结构,采用纳米硬度测试仪和纳米划痕仪研究薄膜的纳米硬度、弹性模量和膜基附着力,在球-盘摩擦试验机上测试薄膜在大气环境中的摩擦学性能,研究薄膜的摩擦学性能与偏压的关系。结果表明:制备的薄膜样品均具有典型的类金刚石碳膜结构;基体偏压强烈影响薄膜的力学和摩擦学性能,薄膜硬度和弹性模量在0～150 V范围内随着偏压增加而增大,薄膜的摩擦因数在偏压为100 V时最小,在此参数下的耐磨寿命也最长。     

Physical properties of ultrafast deposited micro- and nanothickness amorphous hydrogenated carbon films for medical devices and prostheses

Hydrogenated amorphous carbon films with diamond-like structures have been formed on different substrates at very low energies and temperatures by a plasma-enhanced chemical vapour deposition (PECVD) process employing acetylene as the precursor gas. The plasma source was of a cascaded arc type with argon as the carrier gas. The films grown at very high deposition rates were found to have a practical thickness limit of approximately 1.5 microm, above which delamination from the substrate occurred. Deposition on silicon (100), glass, and plastic substrates has been studied and the films characterized in terms of sp3 content, roughness, hardness, adhesion, and optical properties. Deposition rates of up to 20 nm/s have been achieved at substrate temperatures below 100 degrees C. A typical sp3 content of 60-75 per cent in the films was determined by X-ray-generated Auger electron spectroscopy (XAES). The hardness, reduced modulus, and adhesion of the films were measured using a MicroMaterials NanoTest indenter/scratch tester. Hardness was found to vary from 4 to 13 GPa depending on the admixed acetylene flow and substrate temperature. The adhesion of the film to the substrate was significantly influenced by the substrate temperature and whether an in situ d.c. cleaning was employed prior to the deposition process. The hydrogen content in the film was measured by a combination of the Fourier transformation infrared (FTIR) spectroscopy and Rutherford backscattering (RBS) techniques. From the results it is concluded that the films formed by the process described here are ideal for the coating of long-term implantable medical devices, such as prostheses, stents, invasive probes, catheters, biosensors, etc. The properties reported in this publication are comparable with good-quality films deposited by other PECVD methods. The advantages of these films are the low ion energy and temperature of deposition, ensuring that no damage is done to sensitive substrates, very high deposition rates, relatively low capital cost of the equipment required, and the ease of adjustment of plasma parameters, which facilitates film properties to be tailored according to the desired application.     

透射光谱法测试薄膜的光学参数

推导了使用透射光谱极值法来确定薄膜光学参数的理论公式,并对溶胶一凝胶法制作的掺不同浓度二氧化锡的二氧化硅薄膜的折射率和厚度进行了计算。由于透射光谱法来确定薄膜的光学参数时需要其有一定的厚度来形成干涉峰,而用溶胶凝胶浸渍法单次提拉的薄膜厚度太薄,因此用多次提拉的方法来增加厚度。最后借助于柯西色散公式,在其它波段对折射率进行了拟合。结果表明,薄膜的折射率随着二氧化锡含量的增加而增加,相同提拉次数的薄膜厚度也基本相同。     

陷波滤光片的类褶皱设计

针对当前陷波滤光片设计方法中,因需要大量薄层和折射率连续渐变而导致的制作难度较高的问题,介绍了一种陷波滤光片的类褶皱膜系设计方法。此方法中,每层薄膜的层内折射率不变,层间折射率呈离散型渐变,每层为1个光学厚度,膜系模拟计算的光谱很好,并可降低制造工艺难度。给出了膜系的基本结构形式,并分析了其中各参数对陷波滤光片光谱的影响,指出了参数变化对光谱影响的基本规律。通过对典型膜系设计,模拟分析了膜厚偏差和折射率偏差对光谱的影响。结果表明,膜系对膜厚偏差更加敏感,为膜系镀制工艺中的误差控制提供了理论依据。     

A high voltage pulse power supply for metal plasma immersion ion implantation and deposition

We describe the design and implementation of a high voltage pulse power supply (pulser) that supports the operation of a repetitively pulsed filtered vacuum arc plasma deposition facility in plasma immersion ion implantation and deposition (Mepiiid) mode. Negative pulses (micropulses) of up to 20 kV in magnitude and 20 A peak current are provided in gated pulse packets (macropulses) over a broad range of possible pulse width and duty cycle. Application of the system consisting of filtered vacuum arc and high voltage pulser is demonstrated by forming diamond-like carbon (DLC) thin films with and without substrate bias provided by the pulser. Significantly enhanced film∕substrate adhesion is observed when the pulser is used to induce interface mixing between the DLC film and the underlying Si substrate.     

Utilizing a simple and reliable method to investigate the optical functions of small molecular organic films - Alq3 and Gaq3 as examples

This work reports on the optical functions of tris(8-hydroxyquinolinate) gallium and aluminum small molecular organic films grown by utilizing a home-made thermal evaporator and studied with a spectrophotometer. The non-dispersive refractive index of the Gaq3 and Alq3 films was calculated as 1.77 and 1.68, respectively. The higher refractive index of Gaq3 was attributed to the higher molecular packing density of Gaq3 compared to that of Alq3. A larger dielectric constant for Gaq3 was noticed, indicating the presence of a higher density of states and space charge accumulation in the Gaq3 films compared to those of Alq3. We assigned the presence of direct allowed transition to energy gaps of 2.80 eV and 2.86 eV for the Gaq3 and Alq3 films, respectively. These differences are thought to be caused by the effects of central metal cations of Ga³⁺ and Al³⁺ on their molecular quinolinate ligands.     

Time-resolved imaging of laser-induced refractive index changes in transparent media

We describe a method to visualize ultrafast laser-induced refractive index changes in transparent materials with a 310 fs impulse response and a submicrometer spatial resolution. The temporal profile of the laser excitation sequence can be arbitrarily set on the subpicosecond and picosecond time scales with a pulse shaping unit, allowing for complex laser excitation. Time-resolved phase contrast microscopy reveals the real part of the refractive index change and complementary time-resolved optical transmission microscopy measurements give access to the imaginary part of the refractive index in the irradiated region. A femtosecond laser source probes the complex refractive index changes from the excitation time up to 1 ns, and a frequency-doubled Nd:YAG laser emitting 1 ns duration pulses is employed for collecting data at longer time delays, when the evolution is slow. We demonstrate the performance of our setup by studying the energy relaxation in a fused silica sample after irradiation with a double pulse sequence. The excitation pulses are separated by 3 ps. Our results show two dimensional refractive index maps at different times from 200 fs to 100 μs after the laser excitation. On the subpicosecond time scale we have access to the spatial characteristics of the energy deposition into the sample. At longer times (800 ps), time-resolved phase contrast microscopy shows the appearance of a strong compression wave emitted from the excited region. On the microsecond time scale, we observe energy transfer outside the irradiated region.     

Small amplitude reciprocating wear performance of diamond-like carbon films: dependence of film composition and counterface material

Small amplitude (50 μm) reciprocating wear of hydrogen-containing diamond-like carbon (DLC) films of different compositions has been examined against silicon nitride and polymethyl-methacrylate (PMMA) counter-surfaces, and compared with the performance of an uncoated steel substrate. Three films were studied: a DLC film of conventional composition, a fluorine-containing DLC film (F-DLC), and silicon-containing DLC film. The films were deposited on steel substrates from plasmas of organic precursor gases using the Plasma Immersion Ion Implantation and Deposition (PIIID) process, which allows for the non-line-of-sight deposition of films with tailored compositions. The amplitude of the resistive frictional force during the reciprocating wear experiments was monitored in situ, and the magnitude of film damage due to wear was evaluated using optical microscopy, optical profilometry, and atomic force microscopy. Wear debris was analyzed using scanning electron microscopy and energy dispersive spectroscopy. In terms of friction, the DLC and silicon-containing DLC films performed exceptionally well, showing friction coefficients less than 0.1 for both PMMA and silicon nitride counter-surfaces. DLC and silicon-containing DLC films also showed significant reductions in transfer of PMMA compared with the uncoated steel. The softer F-DLC film performed similarly well against PMMA, but against silicon nitride, friction displayed nearly periodic variations indicative of cyclic adhesion and release of worn film material during the wear process. The results demonstrate that the PIIID films achieve the well-known advantageous performance of other DLC films, and furthermore that the film performance can be significantly affected by the addition of dopants. In addition to the well-established reduction of friction and wear that DLC films generally provide, we show here that another property, low adhesiveness with PMMA, is another significant benefit in the use of DLC films.