溅射过程中粒子能量对钛薄膜表面形貌影响

借助于原子力显微镜研究了离子束溅射沉积工艺中入射离子能量对制备的Ti薄膜表面形貌的影响。对薄膜表面高度数据进行相关运算，发现在此工艺条件下制备的薄膜具有典型的分形特征，利用分形表面高度—高度相关函数的唯象表达形式对不同能量下制备Ti薄膜表面的高度相关函数进行拟合。得到了薄膜表面的分形维数、水平相关长度、标准偏差粗糙度等参量。研究发现，入射Ar离子能量在300—700eV之间薄膜表面的粗糙度随着沉积粒子的能量增加而增大，分形维数随着入射离子能量的增加而减少。另外，在得到的分形维数基础上对不同溅射电压下Ti薄膜的生长机制进行了初步研究。     

溅射及其应用

当入射离子能量超过靶材料的溅射阈能时,就会发生溅射现象.离子刻蚀和薄膜生长乃是溅射实际应用中的两个重要方面. 一、溅射的物理基础1.溅射率随寓子入射能量的变化 一个离子轰击靶表面时,被溅射出来的靶原子数目称为溅射率S(原子数/离子).溅射率S随入射离子能量E的变化而变化     

基于原子运动模型的类金刚石薄膜生长机理研究

利用分子动力学模拟方法，从原子尺度上研究了类金刚石(DLC)薄膜生长过程. 按照运动特点把入射原子在表面的行为分为表面冷冻、迁移、注入和反弹等四种，并由此提出原子运动模型. 入射原子的表面行为对DLC薄膜的微观结构以及生长方式有重要影响. 其中原子水平迁移是薄膜热弛豫的主要途径，入射原子的注入和迁移行为相互竞争，决定了薄膜生长的模式和最终结构. 利用统计分析手段给出了入射能量对原子表面行为进而对薄膜结构的影响，加深了对DLC薄膜生长机理的认识.     

金属杂质辅助低能氩离子束诱导蓝宝石自组织纳米结构

使用实验室自主研发的等离子抛光与刻蚀系统,研究了不同入射能量下不锈钢杂质辅助Ar+离子束刻蚀蓝宝石表面自组织纳米结构的形成机制。采用Taylor Surf CCI2000非接触式表面测量仪和原子力显微镜分别对刻蚀后蓝宝石样品的粗糙度、纳米结构的纵向高度和表面形貌进行了分析。研究表明:引入不锈钢杂质后,当离子束入射角度为65°、束流密度为487μA/cm²、刻蚀时间为60 min、离子束入射能量为1000 eV时,蓝宝石样品表面出现了纵向高度为11.1 nm高度有序的条纹状纳米结构;随着入射能量的增加,表面开始出现岛状纳米结构;当入射能量为1200 eV时,形成了岛状与条纹状相结合的纳米结构,其纵向高度为13.6 nm;入射能量继续增加,蓝宝石表面岛状结构密度变大;当入射能量达1400 eV时,样品表面岛状结构的纵向高度为18.8 nm;入射能量为1600 eV时,样品表面出现较为有序且密集的岛状结构,其纵向高度为20.1 nm。自组织纳米结构先是以“条纹”形状出现,随着入射能量的增加,引入的金属杂质打破了在离子束溅射过程中表面生长机制和表面平滑机制的平衡状态,形成了岛状结构,该结构促进了纳米结构的生长,改变了纳米结构的有序性。     

不同能级加速过滤电弧沉积四面体非晶碳膜的结构和性能

采用过滤阴极真空电弧技术，通过施加0—2000 V衬底负偏压使沉积离子获得不同能级的入射能量，在单晶硅上制备了四面体非晶碳薄膜.拉曼光谱分析表明，薄膜的结构为非晶sp³骨架中镶嵌着平面关联长度小于1 nm的sp²团簇.原子力显微镜研究表明：在低能级、富sp³能量窗口和次高能级，薄膜中sp³的含量越多，其表面就越光滑，应用sp³浅注入生长机制能够圆满地解释薄膜表面形态与离子入射能量之间的关系；但在高 关键词： 四面体非晶碳 过滤阴极真空电弧 能级     

入射能量对Au/Au(111)薄膜生长影响的分子动力学模拟

利用分子动力学模拟了Au原子在Au(111)表面低能沉积的动力学过程.采用嵌入原子方法的原子间相互作用势,通过对沉积层原子结构的分析和薄膜表面粗糙度、层覆盖率的计算,研究了沉积粒子能量对薄膜质量的影响及其机制.结果表明:当入射能量Ein25 eV时,沉积层和基体表层均呈现规则的单晶面心立方(111)表面的排列,沉积原子仅注入到基体最表面两层,随着入射能量的增加,薄膜表面粗糙度降低,薄膜越趋于层状生长,入射能量的增加有利于薄膜的成核和致密化;当Ein 25 eV时,沉积层表面原子结构出现了较为明显的晶界,沉积原子注入到基体表面第三层及以下,随着入射能量的增加,薄膜表面粗糙度增加,沉积层和基体表层原子排列越不规则,载能沉积会降低基体内部的稳定性,导致基体和薄膜内部缺陷的产生,降低薄膜质量.此外,当基体内部某层沉积原子数约等于该层总原子数的一半时,沉积原子将能穿过该层进入到基体内部更深层.     

Al(001)表面上沉积Ti薄膜的分子动力学模拟

采用分子动力学模拟方法,研究了Ti原子连续沉积于Al(001)表面上的薄膜生长过程,分析了入射能量为0.1、5 eV和衬底温度为300、700 K时的界面结合及微观结构.模拟结果表明,增加入射能量和衬底温度,使Ti薄膜的表面越光滑;通过径向分布函数和键对分析技术对薄膜微观结构进行分析,发现衬底温度时薄膜微观结构影响较大,温度300 K及以下时,Ti薄膜主要是FCC结构,随着温度升高,FCC结构成分减少,无序结构成分增加,而入射能量则对薄膜微观结构没有明显影响.     

低能Kr+离子束诱导蓝宝石晶体实验研究

使用微波回旋共振离子源制备蓝宝石(A向)自组织纳米结构,研究不同入射角度下Kr+离子束刻蚀蓝宝石表面形成的自组织纳米结构及其形成过程.采用等离子体与离子束刻蚀设备在不同入射角度下对蓝宝石样品表面进行刻蚀并通过Taylor Surf CCI2000非接触式表面测量仪和原子力显微镜分别对刻蚀后的蓝宝石样品的刻蚀速率及表面形貌进行分析.研究表明:当离子束能量为400eV,加速电压为200V,离子束流密度为310μA/cm2时,小角度入射下,蓝宝石样品表面出现纵向尺度较小的有序点状纳米结构;随着入射角度的增加,样品表面形成条纹状纳米结构,30°时形成短程有序且纵横比为0.87的条纹状结构;入射角度继续增加,纵向高度减小直至纳米结构消失;当角度达到60°附近,蓝宝石表面又出现条纹状结构,70°时形成了短程有序且纵横比为1.07的条纹状结构.自组织纳米结构的形成先以"岛状"形式出现,随后岛上生长出条纹状纳米结构,随着刻蚀时间的增加,岛状条纹结构纵向尺度增大且有序性增强,纳米结构的横向周期不变.     

Y稳定的ZrO2薄膜双轴取向生长的Monte Carlo研究

本文采用ＭｏｎｔｅＣａｒｌｏ方法模拟低能Ａｒ＋离子注入ＺｒＯ２单晶所引起的原子级联碰撞过程．模拟结果表明，Ａｒ＋离子沿［１１１］轴沟道方向入射的溅射率低于沿［１０１］轴沟道方向入射的溅射率，更低于沿非沟道方向入射的溅射率．Ａｒ＋离子沿沟道方向入射的溅射率与非沟道方向入射的溅射率的差别随着Ａｒ＋离子入射能量的增大而迅速增大．因此在薄膜生长的过程中，若用一定能量的离子束以一定的入射角度进行轰击，薄膜中那些低指数晶向对准离子入射方向的晶粒，其溅射率和损伤程度较小．这些晶粒能保存下来并继续生长，而其它的晶粒由于其溅射率和损伤程度较大生长受到抑制．在薄膜生长的过程中，溅射率最少的晶粒由于生长速度较快，最终抑制了其它取向晶粒的生长．该模拟计算定性地说明了由于晶粒溅射产额的各向异性导致了Ｙ稳定的ＺｒＯ２薄膜具有单一的取向和平面织构．     

Si2+离子与氢原子碰撞电离过程的CTMC计算

应用经典径迹蒙特卡罗方法研究Si2+离子与氢原子碰撞电离反应过程,计算了随入射离子能量变化的总截面、出射电子随角度和能量变化的一阶、二阶微分截面,及出射电子随入射离子能量变化的平均能量.计算结果展示了软碰撞、电子转移到入射离子连续态、两体相遇碰撞等电离机制.通过计算出射电子到入射离子和靶的距离比的电离电子数分布,研究了不同入射离子能量"鞍点"电离机制的可能性.     

二氧化钛薄膜表面粗糙度研究

为了探究二氧化钛(TiO₂)薄膜表面粗糙度的影响因素, 利用离子束辅助沉积电子束热蒸发技术对不同基底粗糙度以及相同基底粗糙度的K9玻璃完成二氧化钛(TiO₂)光学薄膜的沉积。采用TalySurf CCI非接触式表面轮廓仪分别对镀制前基底表面粗糙度和镀制后薄膜表面粗糙度进行测量。实验表明, TiO₂薄膜表面粗糙度随着基底表面的增大而增大, 但始终小于基底表面粗糙度, 说明TiO₂薄膜具有平滑基地表面粗糙的作用; 随着沉积速率的增大, 薄膜表面粗糙度先降低后趋于平缓; 对于粗糙度为2 nm的基底, 离子束能量大小的改变影响不大, 薄膜表面粗糙度均在1.5 nm左右; 随着膜层厚度的增大, 薄膜表面粗糙度先下降后升高。     

Dependence of the structure of ion-modified NiTi single crystal layers on the orientation of irradiated surface

The composition and structure of Si layers implanted into titanium nickelide single crystals with different orientations relative to the ion beam propagation direction have been studied using Auger electron spectroscopy and transmission electron microscopy. The role of the “soft” [111]_B2 and “hard” [001]_B2 NiTi orientations in the formation of the structure of ion-modified surface layer, as well as the defect structure of the surface layers of the single crystals, has been revealed. Orientation effects of selective sputtering and channeling of ions, which control the composition and thickness of the oxide and amorphous layers being formed, ion and impurity penetration depth, as well as the concentration profile of the Ni distribution over the surface, have been detected.     

Synchrotron study of laser-thermally oxidized thin titanium films

The features of oxidation of thin titanium films on single-crystal silicon have been investigated and the character and mechanism of the action of mid-IR laser radiation on the oxidation of these films in the temperature range 400–500°C have been established. The effects of “laser acceleration” and “laser breaking” of the oxide film growth are revealed. X-ray diffraction data and X-ray absorption near-edge structure spectra of the grown oxides are reported and the change in the phase composition of the oxide films is explained by resonant absorption of laser radiation.     

Allotropic conversion of carbon-related films by using energy beams

Energy beams, such as ion and laser beams, were employed to convert carbon allotropes into other ones at a specified position because these energy sources can be controlled precisely in time and space. The ion beam deposition technique employing mass-separated ions proved effective in studying the nucleation process by changing several growth parameters (ion species, incident energies, and substrate temperatures). Immersed nanosized diamonds were found in an sp ³-rich amorphous film prepared with 100-eV ¹²C⁺ ions at room temperature. Surrounding these nanodiamonds, regularly arrayed small bumps, “petals,” were formed around the periphery of bald circles upon cooling. Ar-ion laser illumination is effective in designing the array of high luminescent points on a C₆₀ film by careful control of the laser power, and the combination of a micro-Raman spectrometer with a piezoscanning system provides one with a tool for 2-dimensional processing of photosensitive materials. Simultaneous bombardment during C₆₀ evaporation results in an interesting pattern formation specific to the simultaneous treatment. The dependence of the surface nanoscale pattern on the ion energy and the substrate temperatures provides one with a new tool for designing nanoscale functional materials. As an extreme, the appearance of hexagonal diamonds was detected with disordered carbon and graphite under the condition of there being a high ratio between the Ne ion beam and the C₆₀ thermal beam.     

斜入射离子束辅助沉积对类金刚石薄膜结构影响的分子动力学模拟

采用分子动力学（MD）模拟方法,从原子尺度上研究了离子束辅助沉积（IBAD）类金刚石（DLC）薄膜过程中离子束入射角对薄膜结构的影响.重点讨论了不同的离子束入射角所对应的薄膜表面模型,平均密度和sp³键含量.结果表明,离子束斜入射加强了入射原子的水平动能,从而加强了原子水平迁移;Ar离子斜入射时C原子迁移率均比垂直入射大,薄膜密度和sp³键含量都比垂直入射小.不同的离子束入射角随着到达比和入射能的变化,对薄膜结构的影响不同.离子束斜入射时可以得到不同结构的膜. 关键词： 类金刚石薄膜 入射角 离子束辅助沉积 分子动力学模拟     

Solid state effects during deuterium implantation into copper and titanium

Results of neutron counting experiments during deuterium implantation into titanium and copper are reported. Models for neutron yield have been developed by taking into account different solid state effects like energy degradation of incident ions, energy dependent d-d fusion cross section and diffusion of implanted deuterium possibly influenced by surface desorption and formation of metal deuterides. The asymptotic time dependence of the neutron yield during implantation has been compared with the experimental results. Using these results, solid state processes that might occur during deuterium implantation into these metals are inferred.     

Surface structure and composition of flat titanium thin films as a function of film thickness and evaporation rate

To correlate flat titanium film surface properties with deposition parameters, titanium flat thin films were systematically deposited on glass substrates with various thicknesses and evaporation rates by electron-beam evaporation. The chemical compositions, crystal structure, surface topographies as well as wettability were investigated by using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM) and water contact angle measurement, respectively. The films consisted mainly of TiO₂. Small percentages of Ti₂O₃ and metallic Ti were also found at the film surface using high-resolution XPS analysis. Quantitative XPS showed little differences regarding elemental compositions among different groups of films. The films were obtained by varying the deposition rate and the film thickness, respectively. XRD data showed consistent reflection patterns of the different titanium samples deposited using different film thicknesses. Without exception measurements of all samples exhibited contact angles of 80° ± 5°. Quantitative AFM characterization demonstrated good correlation tendency between surface roughness and film thickness or evaporation rate, respectively. It is important to notice that titanium films with different sizes of grains on their surfaces but having the same chemistry and film bulk structure can be obtained in a controllable way. By increasing the film thickness and evaporation rate, the surface roughness increased. The surface morphology and grain size growth displayed a corresponding trend. Therefore, the control of these parameters allows us to prepare titanium films with desired surface properties in a controllable and reproducible way for further biological investigations of these materials.     

Die Geschwindigkeitsverteilung von kathodenzerstäubtem Kalium

The differential sputtering ratio (energy spectrum) of polycrystalline potassium sputtered by Ar and Xe ions of 28 keV energy has been measured using surface ionization detection. The spectrum shows a maximum at 0.5 eV and drops to half the maximum value at 2.0 eV. The total sputtering ratio for incident Xe ions is found to be 2.7±1.3 atoms/ion. To check what influence the detector might have on the measured spectrum, different materials and temperatures were used. Below 3 eV the detection probability is energy independent, if the detector is properly heated. Above that energy the measured spectra become uncertain, probably because of the onset of reflexion. Therefore the “focussing energy” of sputtering theory cannot be deduced.     

High sputtering yields of organic compounds by large gas cluster ions

We measured the sputtering yield, surface roughness and surface damage of thin leucine films bombarded with Ar cluster ions and examined the usefulness of large gas cluster ions for the depth profiling of organic compounds. Ar cluster ion beams with a mean size of 2000 atoms/cluster and energies from 5 to 30 keV were used. Sputtering yields increased linearly with incident ion energy and were extremely high compared to inorganic materials. Surface damage was investigated by measuring positive secondary ions emitted from the leucine film before and after cluster ion irradiation. After irradiation the leucine surface became smoother. The yield ratio of protonated leucine ions to other fragment ions kept constant before and after Ar cluster ion irradiation. These results indicate that large gas cluster ions are useful for depth profiling of organic compounds.     

低能Cu13团簇沉积薄膜的分子动力学模拟研究

利用分子动力学模拟方法对Cu₁₃团簇在Fe（001）表面上沉积薄膜进行了研究,分析了不同沉积条件对薄膜生长模式的影响,对比分析了不同沉积条件下表面粗糙度、缺陷分布和外延度等薄膜性质的差异。Cu₁₃团簇的初始沉积能量范围为0.1~10.0 eV/atom,沉积率为1.0 clusters/ps,衬底温度分别为300,700和1 000 K。模拟结果表明:团簇初始沉积能量主要影响薄膜生长模式,当初始沉积能量为7.5 eV/atom的Cu₁₃团簇沉积到温度为300 K的Fe（001）表面时,可形成表面光滑、内部缺陷少和较好外延度的高质量Cu薄膜。