强流脉冲电子束作用下纯镍表层中织构及结构缺陷的演化行为

利用强流脉冲电子束(HCPEB)装置对金属纯Ni进行轰击,采用X射线衍射及透射电子显微镜(TEM)技术详细分析了受轰击样品的变形结构和缺陷。X射线衍射分析表明,经强流脉冲电子束处理后,在{111}和{200}晶面出现了择优取向。TEM表层微观结构分析表明:强流脉冲电子束轰击1次和5次后,晶粒内部形成了大量的(111)[112]型波状条带结构,在波状条带内部包含大量平行的(200)[110]型微条带;10次轰击后,样品变形结构发生变化,除大量的条带状结构外,变形孪晶的数量明显增多。这些变形微结构不仅影响表层的织构演化行为,而且还能细化晶粒,强流脉冲电子束技术为制备表面纳米材料提供了一条有效的途径。     

离子束引起的在Al／Cr双层薄膜界面处的原子混合

用600keV的Kr~ 离子轰击Al/Cr双层薄膜样品进行界面原子反应及相互混合的研究。实验样品是在单晶硅上蒸镀约500nm厚的铝膜,相继再蒸上所需厚度的铬膜而制成的。轰击剂量为2.0×10~(15)-2.5×10~(16)Kr~ /cm~2。用2.0MeVa粒子对轰击前后的样品进行了卢瑟福背散射(RBS)分析,发现界面处有明显的原子混合存在;当轰击剂量≥1.0×10~(16)Kr~ /cm~2时,RBS谱出现有明显的坪台,经拟合计算和x射线衍射(XRD)测量证实确有化合物Al_(13)Cr_2存在;还分别得到了原子混合量及混合效率与轰击剂量的关系;最后对界面处的原子混合机制进行了讨论。     

用YAG激光制备类金刚石薄膜及其光学折射率研究

用高功率的Ｎｄ＾３＋：ＹＡＧ脉冲激光轰击真空室内的石墨靶，形成激光等离子体雾状物质，在硅衬底上沉积形成类金刚石薄膜，用椭圆偏振光谱法测量不同衬底温度下制备的系列样品的厚度和折射率，发现随着衬底温度的升高，薄膜的厚度减小而的折射率增大，这种可以控制折射率米化的薄膜，可能为光学增透增反膜的制备提供一种新方法。     

用IR研究H~+辐照对Mo涂层的影响

在不锈钢基体上采用离子束混合技术及电子束处理方法进行Mo薄膜沉积,沉积后的试样再进行氢离子注入.分别对氢离子注入前后的样品进行500~4000波数范围内IR分析,研究了氢离子辐照前后涂层的红外光谱振动吸收峰的变化,对Mo涂层的抗氢机理进行了探讨.     

强流脉冲电子束作用下纯镍表面的应力特征

 利用强流脉冲电子束（HCPEB）装置对多晶纯镍进行轰击,采用X射线衍射及扫描电子显微镜等技术,详细分析了受轰击样品的变形组织与结构。通过分析建立了强流脉冲电子束诱发的应力特征与变形结构之间的关系,并对目前现有的几种应力波数值模拟结果进行了讨论。实验结果表明：强流脉冲电子束能够在材料表层诱发约5GPa的应力,造成纯镍表面发生孪生塑性变形。除了热膨胀引起的表层横向准静态热应力外,强流脉冲电子束产生的等离子体脉冲爆炸可以直接诱发幅值很高的冲击应力波,二者的共同作用是引起表层微观结构变化的直接原因。     

强流脉冲电子束诱发纯钛表面的微观结构及应力状态

利用强流脉冲电子束(HCPEB)装置对金属纯钛进行轰击,采用X射线衍射,扫描电子显微镜及透射电子显微镜技术详细分析了轰击样品表层的结构和缺陷. X射线衍射分析表明, HCPEB能够在材料表层诱发幅值为 GPa量级的压应力,并在(100), (102)和(103)晶面出现择优取向.表层微观结构的观察表明: HCPEB轰击后材料表层发生了马氏体相变,形成了大量的片状马氏体组织; 此外, HCPEB轰击还在辐照表面诱发了强烈的塑性变形,一次轰击后,晶粒内部的塑性变形以(100)晶面的位错滑移为主,位错密度显著提高;多次轰击后,样品变形结构发生变化,变形孪晶的数量明显增多. 这些变形微结构不仅影响表层的织构演化行为,而且还能细化晶粒,进而提高材料表面硬度, 为HCPEB技术进行纯钛表面强化提供了一条有效的途径.     

两种后处理方法对HfO2薄膜性能的影响

利用电子束蒸发和光电极值监控技术制备了氧化铪薄膜,并分别用两种后处理方法(空气中退火和氧等离子体轰击)对样品进行了处理.然后,对样品的透过率、吸收和抗激光损伤阈值进行了测试分析.实验结果表明,两种后处理方法都能不同程度地降低了氧化铪薄膜的吸收损耗、提高了抗激光损伤阈值.实验结果还表明,氧等离子体轰击的后处理效果明显优于热退火,样品的吸收平均值在氧等离子体后处理前后分别为34.8 ppm和9.0 ppm,而基频(1 064 nm)激光损伤阈值分别为10.0 J/cm2和21.4 J/cm2.     

金刚石/ZnSe结构中瞬态热栅场的有限元法分析

利用有限元法分析计算了脉冲激光激发瞬态热栅在金刚石薄膜/ZnSe衬底双层结构中的三维温度场分布及变化。通过比较不同厚度金刚石薄膜样品的温度场分布,结果显示金刚石薄膜的厚度对样品中温度场的分布有较大影响,随着薄膜厚度的增大,峰值温度提高并且二次加热现象更加明显。     

强流脉冲电子束与固体介质相互作用的研究

采用强流脉冲电子束轰击固体介质样品,研究了强流脉冲电子束与固体介质的相互作用。对晶体中出现的开裂和有机聚合物中出现的树枝状径迹进行了讨论,认为电子束的能量及电荷沉积导致了上述现象。     

MSM结构ZnO/Cu薄膜的接触特性

利用脉冲激光沉积(PLD)法在Si(111)衬底上分别生长了ZnO薄膜和Cu薄膜, 用Cu薄膜作电极,研究了ZnO薄膜与Cu薄膜的接触特性。分别用X射线衍射仪、扫描电子显微镜和I-V测试的方法对样品的晶体质量、结构和电学性质进行了测试。结果表明:样品中ZnO薄膜和Cu薄膜均具有高度的择优取向;当Cu和 ZnO直接接触时,样品的I-V特性是非线性的;当Cu和 ZnO之间通过ZnO:Cu层间接接触时形成良好的欧姆接触,而且退火后欧姆接触性能明显提高,电阻率降低约2/3。本研究为价格低廉的Cu电极成为ZnO基器件的欧姆电极提供了一定的依据。     

Study on the orientation of silver films by ion-beam assisted deposition

Low energy ion beam assisted deposition (IBAD) was employed to prepare Ag films on Mo/Si (100) substrate. It was found that Ag films deposited by sputtering method without ion beam bombardment were preferred (111) orientation. When the depositing film was simultaneously bombardment by Ar⁺ beam perpendicular to the film surface at ion/atom arrival ratio of 0.18, the prepared films exhibited weak (111) and (200) mixed orientations. When the direction of Ar⁺ beam was off-normal direction of the film surface, Ag films showed highly preferred (111) orientation. Monte Carlo method was used to calculate the sputtering yields of Ar⁺ ions at various incident and azimuth angles. The effects of channeling and surface free energy on the crystallographic orientation of Ag films were discussed.     

Room temperature deposition of amorphous SiC thin films using low energy ion bombardment

Silicon carbide (SiC) films are prepared by single- and dual-ion beam sputtering deposition at room temperature, respectively. An assisting argon ion beam (ion energy Ei=150 eV) bombards directly the substrate surface to modify the SiC film surface. The thin films are characterized by the Fourier transform infrared spectroscopy (FTIR) and the Raman spectra. With assisting ion beam bombardment, the density of the Si–C bond in the film increases. Meanwhile, the excess carbon or the size of the sp² bonded clusters and the amorphous Si (a-Si) phase decrease. These results indicate that the composition of the films is mainly Si–C bond. UV-vis transmission shows that the E_opt increases steadily from 1.85 eV for the amorphous SiC (a-SiC) films without bombardment to about 2.29 eV for those with assisting ion beam bombardment.     

Influence of Si substrate preparation on surface chemistry and morphology of L-CVD SnO2 thin films studied by XPS and AFM

Results of experimental studies of the influence of substrate preparation on the surface chemistry and surface morphology of the laser-assisted chemical vapour deposition (L-CVD) SnO₂ thin films are presented in this paper. The native Si(1 0 0) substrate cleaned by UHV thermal annealing (TA) as well as thermally oxidized Si(1 0 0) substrate cleaned by ion bombardment (IBA) have been used as the substrates. X-ray photoemission spectroscopy (XPS) has been used for the control of surface chemistry of the substrates as well as of deposited films. Atomic force microscopy (AFM) has been used to control the surface morphology of the L-CVD SnO₂ thin films deposited on differently prepared substrates. Our XPS shows that the L-CVD SnO₂ thin films deposited on thermally oxidized Si(1 0 0) substrate after cleaning with ion bombardment exhibit the same stoichiometry, i.e. ratio [O]/[Sn] = 1.30 as that of the layers deposited on Si(1 0 0) substrate previously cleaned by UHV prolonged heating. AFM shows that L-CVD SnO₂ thin films deposited on thermally oxidized Si(1 0 0) substrate after cleaning with ion bombardment exhibit evidently increasing rough surface topography with respect to roughness, grain size range and maximum grain height as the L-CVD SnO₂ thin films deposited on atomically clean Si substrate at the same surface chemistry (nonstoichiometry) reflect the higher substrate roughness after cleaning with ion bombardment.     

K9和石英玻璃基片上Au膜真空紫外反射特性研究

采用离子束溅射法,分别在经过不同前期清洗方法处理过的K9及石英玻璃光学基片上,选择不同的镀膜参量,镀制了多种厚度的Au膜。对镀制的Au膜在真空紫外波段较宽波长范围内的反射率进行了连续测量。测试结果表明:辅助离子源的使用方式、Au膜厚度对反射镜的反射率有重大影响。基片材料、镀前基片表面清洗工艺等对反射率也有一定影响。采用镀前离子轰击,可显著提高Au膜反射率及膜与基底的粘合力;获得最高反射率时的最佳膜厚与基片材料、镀膜工艺密切相关。对经过离子清洗的石英基片,膜厚在30 nm左右反射率最高;比较而言,石英基片可获得更高的反射率;辅助离子源的使用还显著影响获得最高反射率时对应的最佳膜厚值,且对K9基片的影响更显著。     

Hybrid laser—magnetron technology for carbon composite coating

Hybrid laser- magnetron deposition system was developed and tested for study of carbon based thin film coatings. Various geometrical configurations and deposition conditions were tested. Films of TiC, TiCN, and SiC were synthesized. Films were fabricated in argon (TiC), in argon/nitrogen (TiCN), or in argon/hydrogen ambient (SiC films). Film properties were studied by SEM, XRD, GDOES, and XPS. Smooth, homogeneous film over the area of 9 cm² were prepared. Crystalline TiC films were grown at room substrate temperature.     

氩离子轰击对四面体非晶碳膜内应力和摩擦系数影响的研究

利用磁过滤真空阴极电弧技术制备了sp³键大于80%的四面体非晶碳(ta-C)薄膜, 通过冷阴极离子源产生keV能量的氩离子轰击ta-C薄膜,研究了氩离子轰击能量对ta-C薄膜结构, 内应力以及耐磨性的影响.通过X射线光电子能谱和原子力显微镜研究了氩离子轰击对薄膜结构 与表面形貌的改性,研究表明,氩离子轰击诱导了ta-C薄膜中sp³键向sp²键的转化, 并且随着氩离子轰击能量的增大,薄膜中sp²键的含量逐渐增多, 薄膜内应力随着氩离子轰击能量的增大逐渐减小.氩离子轰击对薄膜的表面形貌有较大影响, 在薄膜表面形成刻蚀坑,并且改变了薄膜的表面粗糙度,随着氩离子轰击能量的增大, 薄膜的表面粗糙度也会逐渐增大.通过摩擦磨损仪的测试结果,氩离子轰击对薄膜的初始摩擦系数影响较大, 但是对薄膜的稳定摩擦系数影响较小,经过氩离子轰击前后的ta-C薄膜的摩擦系数为0.1左右, 并且具有优异的耐磨性.     

高能氮离子轰击对四面体非晶碳膜的表面改性和摩擦系数影响的研究

利用过滤阴极真空电弧技术制备了sp³键含量不小于80%的四面体非晶碳(ta-C)膜.利用冷阴极潘宁离子源产生不同能量的氮离子对制备的ta-C薄膜进行轰击,通过X射线光电子能谱和原子力显微镜对薄膜表面结构与形貌进行分析研究.研究表明,随着氮离子的轰击能量的增大,薄膜中的CN键结构略有增大,形成了轻N掺杂;同时,在薄膜表层发生了sp³键结构向sp²键结构的转化;薄膜的表面粗糙度在经过氮离子轰击后从0.2 nm减小至0.18 nm,然后随着轰击能 关键词： 四面体非晶碳 X射线光电子能谱 摩擦系数     

基底表面纳米织构对非晶四面体碳膜结构和摩擦特性的影响研究

本文利用离子束表面改性技术对基底表面进行不同时间的轰击, 形成不同规则的纳米织构, 对不同织构的变化规律进行了研究, 同时, 利用磁过滤真空阴极电弧技术, 在具有不同纳米织构的各基底上沉积相同时间的四面体非晶碳薄膜. 采用原子力显微镜对各基底的织构进行形貌分析, 结果表明, 高能粒子束的轰击对基底表面形貌有较大的影响, 根据离子束轰击时间的不同, 可以在基底表面形成各种不同规则的纳米织构, 轰击15 min后发现基底表面形成点阵纳米织构, 之后随着时间的增加, 基本维持点阵结构. 通过X射线光电子能谱仪和摩擦磨损试验仪对沉积在具有不同织构的基底上的ta-C薄膜进行测试, 研究表明, 基底表面纳米织构的非晶层结构引起薄膜内部sp³键的含量降低, 释放了薄膜的内应力, 同时发现基底表面纳米织构将ta-C薄膜磨损时间从不足10 min提高到约70 min, 有效提高了薄膜的耐磨性.     

CVD金刚石中的氮对等离子体刻蚀的影响

采用非对称磁镜场电子回旋共振等离子体分别对沉积过程中掺氮和未掺氮的化学气相沉积金刚石膜进行了刻蚀研究, 结果表明: 掺氮制备的金刚石膜的刻蚀主要集中在晶棱处, 经过4h刻蚀后其表面粗糙度由刻蚀前的4.761 μm下降至3.701 μm, 刻蚀对金刚石膜的表面粗糙度的影响较小; 而未掺氮制备的金刚石膜的刻蚀表现为晶面的均匀刻蚀, 晶粒坍塌,刻蚀4h后其表面粗糙度由刻蚀前的3.061 μm下降至1.083 μm. 刻蚀导致表面粗糙度显著降低. 上述差别的主要原因在于金刚石膜沉积过程中掺氮导致氮缺陷在金刚石晶棱处富集, 晶棱处电子发射加强, 引导离子向晶棱运动并产生刻蚀, 从而加剧晶棱的刻蚀. 而未掺氮金刚石膜,其缺陷相对较少且分布较均匀 ,刻蚀时整体呈现为 (111) 晶面被均匀刻蚀继而晶粒坍塌的现象. 关键词： 掺氮 金刚石膜 刻蚀 非对称磁镜场     

Microstructure and tribological properties of TiN, TiC and Ti(C, N) thin films prepared by closed-field unbalanced magnetron sputtering ion plating

TiN, TiC and Ti(C, N) films have been respectively prepared using closed-field unbalanced magnetron sputtering ion plating technology, with graphite target serving as the C supplier in an Ar-N₂ mixture gas. Bonding states and microstructure of the films are characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) in combination with transmission electron microscopy (TEM). The friction coefficients are measured by pin-on-disc test and the wear traces of deposited films are observed by optical microscope. Results show that the TiN film and Ti(C, N) film exhibit dense columnar structure while the TiC film exhibits a mixed microstructure of main nanocrystallite and little amorphous phases. The Ti(C, N) film has the highest microhardness value and the TiC film has the lowest. Because of small amount of pure carbon with sp² bonds existing in the film, the friction coefficients of Ti(C, N) and TiC multilayer films are lower than that of TiN film. In addition, the multilayer structure of films also contributes visually to decrease of friction coefficients. The TiC film has extremely low friction coefficient while the wear ratio is the highest in all of the films. The results also show that the Ti(C, N) film has excellent anti-abrasion property.