Cu/Zr纳米多层膜的调制结构与电阻率

采用磁控溅射技术在单晶硅片上制备了恒定调制周期(λ=25,40 nm)、不同调制比(η=0.1~10.5)的Cu/Zr纳米多层膜。分别通过透射电子显微镜研究分析Cu/Zr多层膜的微观结构,通过四探针测量法系统研究Cu/Zr多层膜电阻率的尺寸效应。微观结构分析表明:Cu/Zr多层膜呈现周期性层状结构,层界面清晰。调制周期与调制比均显著影响Cu/Zr多层膜的电阻率(ρ)。相同调制周期下,η大于临界调制比(η_C≈1)时,ρ几乎与η无关;而η小于此临界调制比(η_C≈1)时,ρ随η减小急剧增大。利用Fuchs-Sondheimer和Mayadas-Shatzkes(FS-MS)传输模型可以对实验数据进行很好的拟合,拟合结果表明:当ηη_C时,晶界散射和界面散射协同作用是Cu/Zr多层膜电阻率变化的主控机制;当ηη_C时,晶界散射成为多层膜电阻率变化的主导因素。     

HfN/HfB_2纳米多层膜结构调制及其力学性能

为了进一步了解调制周期对HfN/HfB2纳米多层膜力学性能的影响,利用多靶磁控溅射技术,在Si(100)基底上制备了一系列具有相同厚度不同调制周期的HfN/HfB2纳米多层膜。利用XRD、TEM、XP-2台阶仪、纳米压痕仪及摩擦试验机分别分析了多层膜的结构特征、力学性能和室温下摩擦性能。结果表明,室温下沉积的多层膜呈现出结晶/非晶的混合结构;随着调制周期的增大,多层膜的结晶程度先增加后降低,其硬度和弹性模量也呈现出先升高后降低的趋势;当调制周期为40nm时,多层膜的硬度和弹性模量均达到最大值,分别为(36.72±1.3)和(378.41±5.6)GPa,并且此时多层膜具有较高的膜基结合力(Lmax=67.3mN)和较低的平均摩擦系数(0.061);在调制周期为20nm时,多层膜的残余应力达到最小值为-0.82GPa;经过高温退火后,多层膜的硬度和弹性模量均无明显变化,说明其具有良好的热稳定性;多层膜的结构和力学性能随调制周期的变化归因于晶粒的细化。     

ZrN/TiSiN纳米多层膜的微观结构和力学性能研究

采用反应磁控溅射的方法,利用Zr靶与TiSi复合靶成功制备了不同TiSiN层厚度的ZrN/TiSiN纳米多层膜。利用X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、扫描电子显微镜(SEM)和纳米压痕仪研究了不同TiSiN层厚度对ZrN/TiSiN纳米多层膜的微观结构和力学性能的影响。结果表明,ZrN/TiSiN纳米多层膜主要由面心立方的ZrN相组成,随着TiSiN层厚度的增加,纳米多层膜的结晶程度先增加后降低,其硬度和弹性模量也先升高后降低。当TiSiN层厚度为0.7nm时,纳米多层膜具有最高的硬度和弹性模量,分别为28.7和301.1GPa,远超过ZrN单层膜。ZrN/TiSiN纳米多层膜的强化效果可由交变应力场和模量差理论进行解释。     

调制周期对TiB_2/TiAlN纳米多层膜机械性能的影响

利用射频磁控溅射技术,在室温下合成了具有纳米调制周期的TiB2/TiAlN多层膜.分别采用表面轮廓仪、纳米力学测试系统、多功能材料表面性能实验仪和XRD,分析了调制周期对TiB2/TiAlN纳米多层膜机械性能的影响.结果表明大部分多层膜的纳米硬度和弹性模量值都高于两种个体材料混合相的值,在调制周期为25 nm时,多层膜体系的硬度超过了36GPa,性能达到较佳效果.     

Zr基氮化物／金属Cu纳米多层膜的强韧化研究

多层结构可以提高材料的强度、弹性模量和韧性。当尺寸减小到纳米量级时,性能将产生飞跃变化。首先探讨了多层结构提高强度、弹性模量和韧性等性能的基本原理,然后阐明了纳米尺度效应及理论,重点以过渡族金属氮化物ZrN纳米多层膜为例,研究了氮化物／金属（ZrN／Cu）纳米多层膜、ZrAIN纳米复合膜以及ZrAIN／Cu纳米多层膜的强韧化性能。结果表明,ZrN／Cu纳米多层膜的断裂韧性约是二元ZrN薄膜的2倍。当纳米多层膜的Cu单层厚度为2013131时,多层膜的K1C值最高。ZrAIN复合膜的断裂韧性与Al含量密切相关,当Al原子分数为23％时,薄膜的KIc值达3．17MPa·m^1/2,其硬度〉40Gpa,Al原子分数为47％的薄膜的K1C值则降低到1．13MPa·m…。,其硬度降低至17．1GPa。与z州／cu纳米多层膜和ZrAlN复合膜相比,以ZrAIN层和cu层为调制结构制备的ZrAlN／Cu纳米多层膜具有最高的硬度和最好的韧性。     

ZrN/TiAlN纳米多层膜的制备及其结构与性能的研究

利用高真空离子束辅助沉积系统在室温下制备了ZrN,TiAlN和一系列ZrN/TiAlN纳米多层膜,利用X射线衍射仪、纳米力学测试系统和多功能材料表面性能实验仪表征了薄膜的微结构和机械性能,分析了调制周期对薄膜结构与机械性能的影响.结果表明大部分多层膜的纳米硬度与弹性模量值都高于两种个体材料硬度的平均值,当调制周期为6.5 nm时,多层膜硬度达到最高(30.1 GPa),弹性模量、粗糙度、摩擦以及划痕测试均达到最佳效果.     

TiAlN/TiN纳米多层膜的微结构与力学性能

采用多靶反应磁控溅射制备了一系列TiAlN层厚固定,TiN层厚在一定范围内连续变化的不同调制结构的TiAlN/TiN纳米多层膜,并使用X射线衍射分析、扫描电子显微镜、纳米压痕仪和CETR-UMT-3型多功能摩擦磨损试验机对多层膜的微观结构和力学性能进行了表征和分析。研究结果表明:TiAlN/TiN纳米多层膜形成了周期性良好的成分调制结构,其中TiN层的插入并没有打断TiAlN层的柱状晶生长。在一定的调制周期下,TiN层和TiAlN层能够形成共格外延生长结构,多层膜呈现硬度异常升高的超硬效应,当TiN层厚约为1.6 nm时多层膜的硬度达到最大值50 GPa,并具有相比于TiAlN单层膜更低的摩擦系数。进一步增加TiN层厚,由于多层膜共格界面结构的破坏,多层膜的硬度随之降低。     

调制周期对TaN/VN纳米多层膜的影响

本研究选择钽和钒的氮化物作为个体层材料,利用射频磁控溅射系统制备TaN、VN及一系列的TaN/VN多层薄膜。通过XRD和纳米力学测试系统分析了该体系合成以后的晶体结构、调制周期对力学性能的影响。结果表明：多层膜的纳米硬度值普遍高于两种个体材料混合相的硬度值;当调制周期为30 nm时TaN/VN多层膜达到最大硬度31 GPa,结晶出现多元化,多层膜体系的硬度、弹性模量以及耐磨性能均达到最佳效果。     

TiN/NbN纳米多层薄膜的交变应力场和超硬效应

为了研究纳米多层薄膜的超硬效应 ,采用反应溅射法制备从 1 4nm至 2 7nm不同调制周期的一系列TiN/NbN纳米多层膜。高分辨电子显微镜对薄膜的调制结构和界面生长方式的观察发现 ,TiN/NbN膜具有很好的调制结构 ,并呈现以面心立方晶体结构穿过调制界面外延生长的多晶超晶格结构特征。显微硬度测量表明 ,TiN/NbN纳米多层膜存在随调制周期变化的超硬效应。薄膜在调制周期为 8 3nm时达到HK39 0GPa的最高硬度。分析认为 ,两种不同晶格常数的晶体外延生长形成的交变应力场 ,对材料有强化作用 ,这是TiN/NbN纳米多层膜产生超硬效应的主要原因     

c-AIN的生长对AIN/(Ti,Al)N纳米多层膜力学性能的影响

采用反应磁控溅射制备了具有不同调制周期的AIN/(Ti,Al)N纳米多层膜,研究了亚稳相立方氮化铝(c-AIN)在纳米多层膜中的生长条件及其对薄膜力学性能的影响。结果表明:在小调制周期下AIN以立方结构存在,并与(Ti,Al)N层形成同结构共格外延生长,使纳米多层膜产生较大的晶格畸变。与此相应,AIN/(Ti,Al)N纳米多层膜硬度和弹性模量随调制周期的减小呈单凋上升的趋势,当调制周期小于8～10 nm时其增速明显增大,并在调制周期为1.3 nm时达到最高硬度29.0GPa和最高弹性模量383 GPa.AIN/(Ti,Al)N纳米多层膜的硬度和弹性模量在小调制周期时的升高与亚稳相c-AIN的产生并和(Ti,Al)N形成共格结构有关。     

NbN/TaN纳米多层膜的微结构及超高硬度效应

用磁控反应溅射的方法在不锈钢基片上制备了NbN／TaN纳米多层薄膜,试验采用X射线衍射仪（XRD）、透射电子显微镜（TEM）及显微硬度仪对薄膜的微结构和硬度进行分析,结果表明：在NbN／TaN多层膜中,NbN层为面心晶体结构,TaN层为六方晶体结构;NbN／TaN纳米多层膜存在超硬效应,在调制周期2．3～170nm这一放宽的范围内保持超高硬度,硬度最大值HK达51.0GPa     

The effect of annealing on structural, electrical and optical properties of nanostructured ZnS/Ag/ZnS films

In this paper a ZnS/Ag/ZnS (ZAZ) nano-multilayer structure is designed theoretically and optimum thicknesses of ZnS and Ag layers are calculated at 35 and 17 nm, respectively. Several conductive transparent ZAZ nano-multilayer films are deposited on a glass substrate at room temperature by thermal evaporation method. Changes in the electrical, structural, and optical properties of samples are investigated with respect to annealing in air at different temperatures. High-quality nano-multilayer films with the sheet resistance of 8 Ω/sq and the optical transmittance of 83% at 200 °C annealing temperature are obtained. The figure of merit is applied on the ZAZ films and their performance as transparent conductive electrodes are determined.     

TiAlN/VN纳米多层膜的微结构与力学和摩擦学性能

采用反应磁控溅射制备了TiAlN/VN纳米多层膜, 并使用X射线衍射分析(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、纳米压痕仪和多功能摩擦磨损试验机对多层膜的微结构与力学和摩擦学性能进行了表征和分析。研究结果表明: 不同调制周期的TiAlN/VN多层膜均呈典型的柱状晶生长结构, 插入VN层并没有打断TiAlN涂层柱状晶的生长。在一定调制周期下, TiAlN/VN纳米多层膜中的TiAlN和VN层之间能够形成共格生长结构, 其硬度和弹性模量相比于TiAlN单层膜均有显著提升, 其中, TiAlN (10 nm)/VN (10 nm)的硬度和弹性模量最大增量分别达到39.3%和40.9%。TiAlN/VN纳米多层膜的强化主要与其共格界面生长结构有关。另外, TiAlN单层膜的摩擦系数较高(~0.9), 通过周期性地插入摩擦系数较低的VN层能够使得TiAlN的摩擦系数大大降低, TiAlN/VN纳米多层膜的摩擦系数最低为0.4。     

TiN／AIN纳米多层膜的调制周期及力学性能研究

采用一种新型的离子束辅助非平衡反应磁控溅射设备制备了TiN／AlN纳米多层复合膜。采用XRD衍射、TEM、显微硬度计和干涉显微镜对TiN／AlN纳米多层膜的微结构和力学性能进行了表征。结果表明：TiN／AlN多层膜有良好的周期；调制结构影响薄膜的择优取向，薄膜整体表现出硬度增强的效果，硬度随调制周期的变化而变化并在调制周期为7、5nm时达到最大值。     

Interface stress induced hardness enhancement and superelasticity in polytetrafluoroethylene/metal multilayer thin films

Polytetrafluoroethylene (PTFE)/Al, PTFE/Cu, and PTFE/Ti multilayer thin films have been deposited in order to investigate effects of interface energy on mechanical properties. PTFE, which has a low surface energy of 19.2 mJ/m², was used to introduce a large interface energy into multilayer thin films. PTFE thin film was deposited by rf magnetron sputtering using a PTFE sheet target. Al, Cu, and Ti were deposited by dc magnetron sputtering. The multilayer thin films were fabricated sequentially without breaking vacuum. Substrate used was aluminosilicate glass. The modulation period was changed from 6.7 to 200 nm. The total thickness was about 200 nm for all samples. The internal stress of metal layers changed from tensile to compressive and increased with decreasing modulation period for all of PTFE/Al, PTFE/Cu, and PTFE/Ti. Both hardness enhancement and superelasticity were observed in the results of nanoindentation measurements. The energy dissipated during nanoindentation process (one load and unload cycle) decreased with decreasing modulation period. The minimum value of the ratio of dissipated/loaded energy was < 40%, which is smaller than the values obtained for monolithic PTFE or metal films (about 73% for PTFE and 87% for Al, 72% for Cu, and 71% for Ti, respectively). This meant that the PTFE/metal nano-multilayer thin films became more elastic with decreasing modulation period. The tendency of change in the mechanical properties strongly correlated to internal stress. Mechanisms involved in anomalous behaviors in film hardness and elasticity were discussed based on the relationship to interface energy, interface stress, and internal stress, induced by multilayering of the films. It is concluded that a large compressive stress introduced in the thin films increased the energy needed to deform elastically or plastically the thin film during indentation, resulting in the increase in hardness and elasticity. The nanoindentation analysis of the multilayer thin films emphasized that in PTFE/metal multilayer thin films mechanical properties of the films depend on interface stress induced by the accumulated interface energy, being independent of bulk materials properties composing thin films, resulting in increase in hardness and elasticity.     

Fabrication and nano-imprintabilities of Zr-, Pd- and Cu-based glassy alloy thin films

With the aim of investigating nano-imprintability of glassy alloys in a film form, Zr(49)Al(11)Ni(8)Cu(32), Pd(39)Cu(29)Ni(13)P(19) and Cu(38)Zr(47)Al(9)Ag(6) glassy alloy thin films were fabricated on Si substrate by a magnetron sputtering method. These films exhibit a very smooth surface, a distinct glass transition phenomenon and a large supercooled liquid region of about 80 K, which are suitable for imprinting materials. Moreover, thermal nano-imprintability of these obtained films is demonstrated by using a dot array mold with a dot diameter of 90 nm. Surface observations revealed that periodic nano-hole arrays with a hole diameter of 90 nm were successfully imprinted on the surface of these films. Among them, Pd-based glassy alloy thin film indicated more precise pattern imprintability, namely, flatter residual surface plane and sharper hole edge. It is said that these glassy alloy thin films, especially Pd-based glassy alloy thin film, are one of the promising materials for fabricating micro-machines and nano-devices by thermal imprinting.     

Influence of Ag thickness on electrical, optical and structural properties of nanocrystalline MoO3/Ag/ITO multilayer for optoelectronic applications

In this study, MoO₃/Ag/ITO/glass (MAI) nano-multilayer films were deposited by the thermal evaporation technique and then were annealed in air atmosphere at 200 °C for 1 h. The effects of Ag layer thickness on electrical, optical and structural properties of the MoO₃(45 nm)/Ag(5-20 nm)/ITO(45 nm)/glass nano-multilayer films were investigated. The sheet resistance decreased rapidly with increasing Ag thickness. Above a thickness of 10 nm, the sheet resistances became somewhat saturated to a value of 3(Ω/□). The highest transparency over the visible wavelength region of spectrum (85%) was obtained for 10 nm Ag layer thickness. Carrier mobility, carrier concentrations, transmittance and reflectance of the layers were measured. The allowed direct band-gap for an Ag thickness range 5-20 nm was estimated to be in the range 3.58-3.71 eV. The XRD pattern showed that the films were polycrystalline. X-ray diffraction has shown that Ag layer has a (111) predominant orientation when deposited. The figure of merit was calculated for MAI multilayer films. It has been found that the Ag layer thickness is a very important factor in controlling the electrical and optical properties of MAI multilayer films. The optimum thickness of the Ag layer for these films was determined. The results exhibit that the MAI transparent electrode is a good structure for use as the anode of optoelectronic devices.     

超硬纳米多层膜致硬机理研究

本文综述了近年来纳米多层膜界面微结构及超硬效应的研究进展, 表明纳米多层膜硬化的主要机制和位错的运动相关, 晶格错配引起的交变应变场对硬化起次要作用, 模量差异致硬起主要作用. 指出了超硬纳米多层膜研究所存在的问题以及未来的发展方向.     

Precipitation and aging in high-conductivity Cu–Cr alloys with additions of zirconium and magnesium

Abstract

The precipitation reactions responsible for age hardening in a high-conductivity Cu–Cr–Zr–Mg alloy have been investigated by analytical transmission electron microscopy and compared briefly with the processes that occur in simpler Cu–Cr and Cu–Cr–Mg alloys. Aging at low temperatures (400°C) results in the formation of Guinier–Preston zones. Peak hardness, obtained by aging for 24 h at 450°C, is found to be a result of the fine scale precipitation of an ordered compound, possibly of the Heusler type, with the suggested composition CrCu₂(Zr, Mg). Overaging results in the formation of coarse precipitates of Cr and CU₄Zr. The intergranular precipitate which forms in the Cu–Cr–Zr–Mg alloy is Cu₄Zr. This phase precipitates both as discrete particles on the grain boundaries and as thin ( ~ 5 nm) continuous intergranular films.

MST/89