衬底负偏压对溅射Ta2O5薄膜晶化温度及介电性能的影响

采用磁控溅射法，在衬底温度为620℃时，通过引入合适的衬底负偏压(100—200V)，获得了结晶良好的Ta2O5薄膜．衬底负偏压增强了正离子对衬底表面的轰击作用，加速了其在衬底表面的松弛扩散效应，从而降低了Ta2O5薄膜的晶化温度，改善了其结晶性．同时，G—V测试结果表明：衬底负偏压进一步改善了Ta2O5薄膜的介电性能．     

Al基上偏压磁控溅射Cu薄膜的工艺研究

利用磁控溅射方法,通过对衬底施加负偏压吸引等离子体中的阳离子对衬底进行轰击,在Al箔上制备Cu薄膜.采用强力胶带试验及数字式微欧计考察了负偏压对薄膜附着力和方块电阻的影响,以及Cu薄膜的氧化规律.结果表明,样品的附着力随负偏压的增大先急剧增加,后又下降,负偏压为200 V时附着力最强,为76 N;方块电阻则随负偏压的增大先下降,在200 V达到最小值1.575 Ω/□,而后又增大;Cu薄膜的氧化反应完成的时间与Cu膜厚度基本呈线性规律.     

负衬底偏压对碳纳米管生长的影响

利用负衬底偏压增强热灯丝化学气相沉系统制备了碳纳米管，用扫描电子显微镜研究了碳纳米管的生长，结果表明碳纳米管的生长随着负衬底偏压的增大先增强，然后减弱，并且出现了部分准直的碳纳米管，分析和讨论了负衬底偏压对碳纳米管生长的影响。     

负偏压增强金刚石膜与衬底结合强度的理论研究

由于金刚石与Si有较大的晶格失配度和表面能差,利用化学气相沉积(CVD)制备金刚石膜时,金刚石在镜面光滑的Si表面上成核率非常低.而负衬底偏压能够提高金刚石在镜面光滑的Si表面上的成核率,表明金刚石核与Si表面的结合力也得到增强.利用负偏压增强CVD系统制备金刚石膜时,气体辉光放电产生的离子对Si表面轰击,使得Si衬底表面产生了微缺陷(凹坑),增大了金刚石膜与Si衬底的结合面积.本工作主要从理论上研究离子轰击对金刚石膜与Si衬底结合力的影响.     

衬底负偏压对线性离子束DLC膜微结构和物性的影响

采用一种新型线性离子束PVD技术制备出大面积类金刚石薄膜(DLC膜),研究了衬底负偏压对薄膜微结构和物性的影响.结果表明:制备出的类金刚石薄膜在300 mm×100 mm范围内纵向厚度均方差约10-12 nm,横向薄膜厚度均方差约2-4 nm.随着衬底偏压的提高,薄膜中sp~3键的含量先增加后减小,在衬底偏压为-100 V时sp~3键的含量最大;DLC膜的残余应力、硬度和弹性模量与sp~3键的含量呈近似线性的关系,在衬底偏压为-100 V时其最大值分别为3.1 GPa、26 GPa和230 GPa.DLC薄膜的摩擦学性能与薄膜中sp~3碳杂化键的含量密切相关,但是受衬底偏压的影响不大,其摩擦系数大多小于0.25.偏压对磨损的影响很大,在偏压比较低(0～-200 V)时,薄膜的磨损率约为10~(-8)mm~3/N·m,偏压升高到300 V磨损率急剧提高到10~(-7)mm~3/N·m.     

脉冲偏压对等离子体沉积DLC膜化学结构的影响

以乙炔为气源，用等离子体基脉冲偏压沉积（plasma based pulsd bias deposition缩写PBPBD）技术进行了不同负脉冲偏压条件下制备DLC膜的试验，通过X射线光电子谱（XPS）、激光喇曼光谱[Raman]以及电阻分析方法考察了负脉冲偏压幅值对DLC膜化学结构的影响，结果表明由-50kV到-10kV随负脉冲偏压降低，DLC膜中SP^3键分数单调增加，但当脉冲偏压为0时形成高电阻的类聚合物膜，说明荷能离子的轰击作用形成DLC化学结构的必要条件，键角混乱度和SP^2簇团尺寸与脉冲偏压之间不具有单调关系，在中等幅值负脉冲偏压条件下，键用混乱度较大且SP^2簇团尺寸细小。     

负偏压在碳纳米管生长过程中的作用研究

利用负偏压增强热丝化学气相沉积系统,在沉积有过渡层Ta和催化剂层NiFc的Si衬底上制备得到了碳纳米管.研究发现,负偏压对NiFe层的裂解和碳纳米管的生长都有很大的影响.本文详细分析和讨论了负偏压在碳纳米管生长过程中的作用.     

基板负偏压对A3钢基体磁控溅射离子镀铝膜相组成的影响

本文主要论述基板负偏压与A3钢基体磁控溅射离子镀铝膜相组成的关系。磁控溅射离子镀铝膜不是简单的单质外接铝膜,而是铝和铁组成的合金膜。膜的相组成主要是基板负偏压所决定的。在一定的实验条件下,每种铁—铝合金相的出现都有一临界基板负偏压与之对应。     

不同晶态比条件下氢化纳米硅薄膜光学性质的研究

利用等离子体化学气相沉积系统,在射频源和直流负偏压源的双重激励下,保持射频功率、反应室气压、衬底温度、硅烷与氢气混合比以及总流量不变,改变直流负偏压从50～250V,在康宁7059玻璃衬底上制备了本征氢化纳米硅薄膜。利用拉曼散射仪表征了不同直流负偏压条件下薄膜微结构特征;利用Shmadzu UV-2450型光谱仪测试了薄膜样品透射图谱。研究发现提高直流负偏压将导致晶态比、沉积速率发生变化。薄膜的光吸收系数和消光系数随波长增加呈下降趋势;不同晶态比薄膜的悬挂键和有效载流子浓度、致密程度、键畸变程度和悬挂键数目的差异,致使晶态比增加,薄膜的吸收系数、消光系数在波长为400nm附近依次增加,光学带隙值从1.96eV减小到1.66eV。     

偏压对CrN/Si3N4纳米多层膜结构、硬度和断裂韧性的影响

利用磁控溅射法在不同基底偏压条件下制备了CrN/Si3N4纳米多层膜,分别用X射线衍射仪、原子力显微镜及纳米压痕仪表征多层膜的微观结构及力学性能,结果表明,衬底偏压对CrN/Si3N4纳米多层膜微观结构、界面结构、硬度和磨损性能有重要影响。漂浮电位时多层膜界面粗糙,CrN呈(200)、(111)共同生长,硬度和弹性模量低,有偏压且变化时界面宽度和粗糙度变化不大,硬度和模量变化的主要原因是不同衬底偏压下的晶格畸变导致两层材料弹性模量变化和晶粒尺寸变化。基底偏压的优化有助于改善涂层的屈服应力和断裂韧性。     

非晶金刚石薄膜的拉曼光谱研究

碳离子的能量是影响非晶金刚石薄膜结构和性质最关键的工艺参数．采用磁过滤真空溅射离子技术,研究不同衬底偏压Ｖ_ｂ（即不同碳离子能量）下制备的非晶金刚石薄膜的拉曼光谱和表面形貌．结果表明：－５０Ｖ≤Ｖ_ｂ≤－１０Ｖ时,样品表面均匀、光滑,拉曼谱是对称且很宽的散射带;Ｖ_ｂ＞－１０Ｖ或Ｖ_ｂ＜－５０Ｖ时,已有晶团出现,表面粗糙度明显增加,拉曼谱明显地分裂为１５８０ｃｍ^－１的Ｇ带和１３５０ｃｍ^－１的Ｄ带．     

Enhancing effect of substrate bias on nanotwin formation of sputtered Ag thin films

In this study, a novel method for producing high-density 〈111〉-oriented nanotwinned Ag film is proposed so as to improve the performance of backside metallization for power devices. Negative bias voltages were applied during sputtering to facilitate the formation of densely stacked nanotwinned columnar structures. In addition, the effects of substrate bias on the properties of Ag films were observed in the lower transition layer thickness, stronger 〈111〉 texture, and higher indentation hardness. The optimal indentation hardness, 1.71 GPa, was found in the nanotwinned Ag film sputtered with a bias voltage of???150 V; it was about twice that of the normal-grained Ag film sputtered without substrate bias, 0.85 GPa. In addition, the results showed that the Ag film sputtered with a bias voltage of???150 V possessed the strongest (111) intensity, and its surface (111) ratio was 98%, much higher than the 77% of the Ag film sputtered without substrate bias. It is concluded that the Ag nanotwinned film sputtered with a bias voltage of???150 V has the potential for application as an interlayer in low-temperature direct bonding.

     

用XPS和AFM等方法研究氮化钛薄膜的物理化学特性

采用反应非平衡磁控溅射方法制备了氮化钛(TiN)薄膜,沉积时的衬底偏压的范围从0V到-500 V.实验结果表明:TiN薄膜的物理特性和力学性能随衬底偏压变化,最佳的薄膜硬度与弹性模量在偏压为-100 V时得到.AFM的测量结果显示薄膜的表面形貌和粗糙度随衬底偏压变化有一个非线性的变化趋势,同样的趋势也出现在Ti2p和N1s的芯态能谱上.特定谱峰的强度和位置的变化预示着偏压引起的薄膜成分和化学态的变化,XPS的结果表明:适当的偏压有助于TiN的成键,稳定的化学结构防止了表面的氧化和扩散,抑制了杂质和缺陷的形成,良好的机械特性归于表面形貌的改善.     

Boron carbide coatings prepared by cathodic arc deposition

Boron carbide films are attractive materials for use as tribologcal coatings for low and high operating temperatures, especially for applications that require high hardness. The properties of boron carbide films prepared by cathodic arc using a heated B₄C cathode are investigated. The B:C ratio in the film was about 3, and the only detected impurity was oxygen with a content below 5%. The effect of substrate bias on the film characteristics was studied. A direct correlation between hardness and elastic modulus and bias voltage applied to the substrate was observed for bias voltages in the interval of 0–500 V. Microstructure and chemistry of the films were investigated using X-ray diffraction, electron microscopy and X-ray absorption spectroscopy.     

约瑟夫森结Nb电极的实验研究

通过溅射Nb膜张力与氩（Ar）压强的关系，超导转变温度Tc，室温阻扰与液氮温度阻抗比RRT／RLN2，沉积中Ar浓度CAr与负偏压关系的测量和扫描电子显微镜的观察分析，对约瑟夫森结Nb电极作了研究。发现Ar压强在1．1Pa时，Nb膜呈现无应力状态；低负偏压下沉积的Nb膜晶粒结构是由致密膜到圆柱状。在偏压Ub＝－50V时，获得表面致密均匀、晶粒结构合适的Nb膜。对Nb膜用阳极氧化电压谱图（AVS）分析，证实沉积的Nb膜内不存在氧化物、寄生结和分层界面。     

Substrate bias voltage influenced structural, electrical and optical properties of dc magnetron sputtered Ta2O5 films

Tantalum oxide (Ta₂O₅) films were formed on silicon (111) and quartz substrates by dc reactive magnetron sputtering of tantalum target in the presence of oxygen and argon gases mixture. The influence of substrate bias voltage on the chemical binding configuration, structural, electrical and optical properties was investigated. The unbiased films were amorphous in nature. As the substrate bias voltage increased to −50 V the films were transformed into polycrystalline. Further increase of substrate bias voltage to −200 V the crystallinity of the films increased. Electrical characteristics of Al/Ta₂O₅/Si structured films deposited at different substrate bias voltages in the range from 0 to −200 V were studied. The substrate bias voltage reduced the leakage current density and increased the dielectric constant. The optical transmittance of the films increased with the increase of substrate bias voltage. The unbiased films showed an optical band gap of 4.44 eV and the refractive index of 1.89. When the substrate bias voltage increased to −200 V the optical band gap and refractive index increased to 4.50 eV and 2.14, respectively due to the improvement in the crystallinity and packing density of the films. The crystallization due to the applied voltage was attributed to the interaction of the positive ions in plasma with the growing film.     

X-ray reflectivity study of bias graded diamond like carbon film synthesized by ECR plasma

Diamond like carbon (DLC) coatings were deposited on silicon substrates by microwave electron cyclotron resonance (ECR) plasma CVD process using plasma of Ar and CH ₄ gases under the influence of negative d.c. self bias generated on the substrates by application of RF (13·56 MHz) power. The negative bias voltage was varied from ?60 V to ?150 V during deposition of DLC films on Si substrate. Detailed X-ray reflectivity (XRR) study was carried out to find out film properties like surface roughness, thickness and density of the films as a function of variation of negative bias voltage. The study shows that the DLC films constituted of composite layer i.e. the upper sub surface layer followed by denser bottom layer representing the bulk of the film. The upper layer is relatively thinner as compared to the bottom layer. The XRR study was an attempt to substantiate the sub-plantation model for DLC film growth.     

反应溅射TiN纳米晶薄膜的结构特征和耐蚀性

利用直流反应溅射技术在不锈钢和硅基体上沉积了TiN纳米晶薄膜,采用场发射扫描电镜(FESEM)、X射线衍射(XRD)和电化学阻抗谱(EIS)技术研究了薄膜的表面形貌、相结构和耐蚀性与偏压的关系。结果表明,TiN薄膜的表面结构明显取决于所施加的偏压,适当提高偏压有利于获得细小、均匀、致密和光滑的膜层。XRD分析发现,TiN薄膜为面心立方结构,其择优取向为(111)面。实验显示,对应0V和-35V偏压的薄膜为欠化学计量比的,而偏压增加至-70V和-105V时的薄膜为化学计量比的TiN。EIS结果表明,较高偏压下的TiN薄膜几乎在整个频率范围内均表现为容抗特征,其阻抗模值明显高于低偏压下的膜层,这主要与较高偏压下的薄膜具有相对致密的微结构有关。较低偏压的TiN薄膜因结构缺陷较多其耐蚀性低于基体不锈钢。EIS所揭示的薄膜结构特征与FESEM观测结果一致。可见,减少穿膜针孔等结构缺陷有利于改善反应溅射TiN纳米晶薄膜耐蚀性。     

Diffusion barrier capability of Zr-Si films for copper metallization with different substrate bias voltage

Efficiency of Zr-Si diffusion barriers in Cu metallization has been investigated. Amorphous Zr-Si diffusion barriers were deposited on the Si substrates by reactive magnetron sputtering with different negative substrate bias. The mass density of Zr-Si films increases with substrate bias voltage up to − 150 V. The deposition rate decreased with the negative substrate bias from 5.4 nm/min to 1.8 nm/min. XRD measurements show that the Zr-Si barriers have amorphous structure in the as-deposited state. The FE-SEM images show that the sizes of spherical granules on the Zr-Si film surface increase with increasing the substrate bias. The Cu/Zr-Si/Si structures were prepared and annealed in Ar ambient at temperatures varying from 500 to 650 °C for an hour. It is shown from the comparison study that the Zr-Si film deposited with − 150 V is better at maintaining good performance in Cu/Zr-Si/Si contact system than that of Zr-Si film deposited with − 50 V.     

Multilayer antireflective and protective coatings comprising amorphous diamond and amorphous hydrogenated germanium carbide for ZnS optical elements

To effectively protect and improve the transmittance of ZnS optical elements in the far infrared band, combined amorphous diamond (a-D) and amorphous hydrogenated germanium carbide (a-Ge_1−xC_x:H) films have been developed. The optical interference coatings were designed according to the layer optics theory. The a-D films, of which refractive index and film thickness were controlled by changing substrate bias and deposition time respectively, were deposited by filtered cathodic vacuum arc technology. The a-Ge_1−xC_x:H films were prepared by radio frequency sputtering technology. During this process their refractive index was modulated by changing the gas flow rate ratio and their film thickness was controlled by the flow rate ratio and deposition time. It has been shown that the combined films are superexcellent antireflective and protective coatings for ZnS optical elements.