紫外光辐照下钛硅共掺杂类金刚石薄膜微结构的演化

采用中频磁控溅射Ti80Si20合金靶在单晶硅表面制备了钛硅共掺杂的类金刚石薄膜。利用紫外-可见光多波长Raman光谱表征薄膜微结构, 并结合FTIR光谱研究了紫外光辐照对类金刚石薄膜微结构的影响, 进一步讨论了紫外光辐照下薄膜微结构的演化机理。结果表明: 非晶结构的类金刚石薄膜出现反式聚乙炔和聚对苯乙炔类聚合物结构以及sp杂化的线型卡宾碳结构。紫外光辐照诱导薄膜微结构驰豫和重构, 薄膜Si-O和C-O键含量增加, C=C和C-H键含量减少; 同时薄膜sp²团簇尺寸减小而无序度增大。     

类金刚石薄膜的辐照及其发展

类金刚石薄膜（以下简称ＤＬＣＦ）是一种极有发展前途的材料,其用途非常广泛。介绍ＤＬＣＦ辐照的现状,指出ＤＬＣＦ辐照效应的研究对其在空间、核聚变反应等辐照环境下应用的必要性和重要性,预测了其发展方向和应用前景。     

类金刚石薄膜的微结构及其电学性质的研究

通过透射－反射谱,红外光谱表征了类金刚石ａ－Ｃ：Ｈ：Ｎ薄膜微结构与氮含量的关系。实验结果表明,随Ｎ２／Ａｒ气体流速比的增加,在ａ－Ｃ：Ｈ：Ｎ膜内Ｎ－Ｈ含量增加,Ｃ－Ｈ含量减少。     

γ射线辐照对类金刚石薄膜结构与特性的影响

用射频等离子体方法在玻璃基底上制备了类金刚石薄膜。分析了γ射线辐照类金刚石薄膜（以下简称ＤＬＣ薄膜）的结构与特性改变。采用Ｒａｍａｎ及红外光谱进行结构分析表明：随辐照剂量的增加，在膜中出现ＳＰ３Ｃ—Ｈ及 ＳＰ２Ｃ—Ｈ 键的断裂与减少，ＳＰ３Ｃ—Ｃ键的略微增加．当辐照剂量达 １０ ×１０４Ｇｙ时，ＳＰ３Ｃ—Ｈ键减少约５０％，与此同时，出现膜中氢的重新键合，并从中释出。γ射线辐照使ＤＬＣ薄膜的电阻率呈上升趋势，膜的类金刚石特征更加明显，结构得到改善。本文对γ射线对ＤＬＣ薄膜的辐照机制进行了简要的讨论。     

纳秒激光辐照对类金刚石薄膜的损伤及改性

利用Nd:YAG纳秒激光(波长分别为355、532和1 064 nm)辐照由电子束蒸发技术制备的类金刚石(DLC)薄膜,通过光学显微镜、光学轮廓仪和拉曼光谱仪等分析了辐照后的薄膜样品,结果表明:不同波长的单脉冲激光辐照时,DLC膜的激光损伤阈值不同;同一波长的多脉冲激光辐照时,损伤阈值低于单脉冲辐照阈值;脉冲激光辐照对DLC膜具有改性作用,受辐照薄膜区域表层发生了石墨化、剥落和气化效应,致使DLC膜表面出现了隆起和弹坑,隆起高度和弹坑深度与激光能量密度大小和脉冲个数有关.     

异丙醇溶液中电化学法制备类金刚石薄膜的研究

采用电化学方法,以分析纯的异丙醇溶液作为碳源,低温(60～70℃)常压条件下,在(100)硅片上沉积了类金刚石薄膜.利用扫描电子显微镜( SEM)、原子力显微镜(AFM)、拉曼光谱仪(Raman)和傅里叶变换红外光谱仪(FTIR)表征了薄膜的表面形貌和结构.结果表明,电解异丙醇溶液可以获得表面均匀致密且sp3碳含量较高的含氢类金刚石薄膜.     

掺氮类金刚石薄膜激光退火的Raman光谱研究

采用功率密度分别为300,750和1500W／mm^2的氩离子激光器,对由射频等离子化学气相沉积（RF－CVD）法制备的掺氮类金刚石薄膜进行了激光退火处理。并用傅立叶红外吸收光谱和显微Raman等手段,对所得样品进行研究。结果表明：C－N键比C－H键更为稳定,一方面氮原子的引入制约了C－H键的生成,在激光退火中减少了因C－H键分解而引起薄膜的石墨化;另一方面生成的C－N键不易受热分解;因此随着氮含量的增加,薄膜中C－N成分增加,从而提高了类金刚石薄膜的热稳定性。     

掺氮类金刚石薄膜激光退火的Raman光谱分析

采用显微拉曼光谱研究的掺氮的类金刚石薄膜,该薄膜分别经过能量密度为300,750和1500W/mm^2氩离子激光的退火处理。分析结果表明氮原子在类金刚石薄膜中形成了C-N键制约了C-H键的形成。由于C-N键的键能比C-H键的键能大得多。因此在激光退火过程中C-N键不易分解,所以随着氮含量的增加,类金刚石薄膜的激光退火后石墨化程度明显降低,具有比较好的热稳定性,而非掺氮的类金刚石薄膜由于C-H键含量比较高,因此激光退火后容易石墨化。     

类金刚石薄膜的耐热性研究进展

类金刚石薄膜具有良好的物理化学性能、光电性能、机械性能及摩擦学性能。但是在高于400℃的温度条件下，DLC膜易向石墨结构转变，从而阻碍了其在高温条件下的应用。因此关于类金刚石薄膜耐热性的研究是目前的一个热门研究课题。在综合分析近年来该领域研究的基础上总结了影响DLC膜耐热性的3种因素：膜结构、掺杂、制备方法，并分析了各种因素的影响机理。     

掺氮类金刚石薄膜的微观结构和光学特性研究

采用射频等离子增强化学气相沉积法( PECVD)制备掺氮类金刚石薄膜(DLC:N),通过原子力显微镜,拉曼光谱和椭圆偏振光谱等对试验样品进行研究,实验结果表明,在薄膜中,氮元素主要以C=N键的形式存在,起到了降低薄膜内应力,提高薄膜附着力的作用;此外,通过控制掺氮量可以制得折射率在1.85～1.6范围内的DLC薄膜.     

Effects of SiNx interlayer on characterisation of amorphous diamond-like carbon films

The magnetron sputtering amorphous diamond-like carbon film is successfully deposited by SiN_x interlayer approach. The scanning electron microscopy study reveals the creation of high uniform surface micrograph diamond-like carbon films with SiN_x interlayer. For comparison, diamond-like carbon films with different interlayers are also grown. The Raman spectra are analyzed in order to characterize the stressed induce peak shifts of the films. The interactions of C atom with Si(100) and SiN_x surface are studied by density functional theory simulation. The effects of interlayers on the films deposition and the considering deposition mechanism are discussed. It is suggested that the diamond-like carbon and SiN_x bilayer structure can help to render applications in protective coatings and high quality silicon on diamond related radiation tolerance devices.     

The influence of nanosecond pulse laser irradiation on the properties of a-C:H films

Plasma-deposited amorphous hydrogenated carbon (a-C:H) films are determined both by the carbon sp³/sp² bonding ratio and the hydrogen content. As the energy of the bonds C-H (C-C) is considerably smaller than that of CC or CC bonds, so the hydrogen concentration and the physical properties of a-C:H films can be varied by laser irradiation. The properties of produced films were investigated by Rutherford backscattering (RBS) and elastic recoil detection (ERD) spectroscopy, null-ellipsometry, and Raman spectroscopy (RS). It was found that films with higher hydrogen concentration are more sensitive to nanosecond pulse laser irradiation.     

Oxygen plasma etching of silver-incorporated diamond-like carbon films

Diamond-like carbon (DLC) film as a solid lubricant coating represents an important area of investigation related to space devices. The environment for such devices involves high vacuum and high concentration of atomic oxygen. The purpose of this paper is to study the behavior of silver-incorporated DLC thin films against oxygen plasma etching. Silver nanoparticles were produced through an electrochemical process and incorporated into DLC bulk during the deposition process using plasma enhanced chemical vapor deposition technique. The presence of silver does not affect significantly DLC quality and reduces by more than 50% the oxygen plasma etching. Our results demonstrated that silver nanoparticles protect DLC films against etching process, which may increase their lifetime in low earth orbit environment.     

Implantation effect of diamond-like carbon films by 110 keV nitrogen ions

Diamond-like carbon films, grown on microscope slides by a dual-ion beam sputtering system, were implanted by 110 keV N⁺ under the doses of 1 × 10¹⁵, 1 × 10¹⁶ and 1 × 10¹⁷ions cm⁻² respectively. The implantation induced changes in electrical resistivity of the films and in infrared (IR) transmittance of the specimens were investigated as a function of implantation dose. The structural changes of the films were also studied using IR spectroscopy and Raman spectroscopy. It was observed that, with the increase of implantation dose, the diamond-like carbon films display two different stages in electrical and optical behaviours. The first is the increase of both the film resistivity and the IR transmittance of specimen at the dose of 1 × 10¹⁵ ions cm⁻² which, we consider, is attributed to the implantation-induced increase sp³ C---H bonds. However, when the doses are higher than 1 × 10¹⁵ ions cm⁻², the film resistivity and the IR transmittance of specimen decrea significantly and the decrease rates at dose range of 1×10¹⁶ to 1×10¹⁷ ions cm⁻² are smaller than those between 1×10¹⁵ and 1 × 10¹⁶ ions cm⁻². We conclude that the significant reductions of the two parameters at high doses are caused by the decreases of bond-angle disorder and of sp³ C---H bonds, the increases of sp² C---C bonds dominated the crystallite size and/or number and also the sp² C---H bonds. The smaller decrease rates at a dose range of 1 × 10¹⁶ to 1 × 10¹⁷ ions cm⁻² may be caused by further recombination of some retained hydrogen atoms to carbon atoms.     

Study of diamond-like carbon films on LiNbO3

Diamond-like carbon (DLC) films have been successfully deposited on Y-cut LiNbO₃ substrates using the plasma enhanced CVD technique. A thin interlayer of SiC between the DLC films and the LiNbO₃ is necessary to ensure a good adhesion of the DLC films to the LiNbO₃ substrate. The physical properties and structural network of the DLC films have been investigated in detail. It is observed that the film hardness is increased with increasing the film thickness, as is the adhesion of the DLC films to the LiNbO₃ substrates. The effect of accelerating surface acoustic wave by the DLC films has been confirmed.     

激光辐照对类金刚石薄膜改性及损伤研究

介绍了激光损伤的检测及损伤阈值的测量方法.讨论激光辐照对类金刚石结构和性质的影响规律.并论述不同工作参数的激光对类金刚石薄膜的激光破坏行为及其损伤阈值.在此基础上分析类金刚石薄膜激光损伤的机理.还从物理特性及制备技术方面着手,比较分析金刚石及类金刚石薄膜各自的优缺点和实际应用状况,并提出类金刚石薄膜的应用前景和有待进一步研究的问题.     

Studies of diamond-like carbon films prepared by ion beam-assisted deposition

Ion beam-assisted deposition offers a novel and unique process to prepare diamond-like carbon (DLC) films at room temperature, with particularly good interface adhesion. This advantage was explored in this study to deposit highly wear-resistant coating on bearing 52100 steel. Both dual ion beam sputtering and ion beam deposition were employed. Various bombarding species and energy were investigated to optimize the process. Raman, X-ray photoelectron and Auger electron spectroscopy were used to characterize the bonding structure of DLC. Extensive experiments were carried out to examine the tribological behaviour of the DLC/52100 system. A metal intermediate layer can help tremendously in wear resistance. The results are optimistic and may lead to useful applications.     

The influence of fluorine doping on the optical properties of diamond-like carbon thin films

Optical properties of fluorine doped diamond-like carbon (F:DLC) films deposited by the direct current plasma enhanced chemical vapor deposition (PECVD) technique were studied in detail. Surface morphologies of the F:DLC films were studied by an atomic force microscope, which indicated surface roughness increased with increase in at.% of F in the films. The chemical binding was investigated by X-ray photoelectron spectroscopic studies. Fourier transformed infrared spectroscopic studies depicted the presence of CF_x (x = 1,2,3) and CH_n (n = 1,2) bonding within the F:DLC films. Optical transparency and the optical band gap decreased with the fluorine incorporation in the DLC film. Optical band gap calculated from the transmittance spectra decreased from 2.60 to 1.95 eV with a variation of 0-14.8 at.% of F concentration in the diamond-like carbon films. Urbach parameter determined from the band tail of the transmittance spectra showed that it increased with the doping concentration.     

Investigation of the properties of diamond-like carbon thin films deposited by single and dual-mode plasma enhanced chemical vapor deposition

In this study diamond-like carbon (DLC) films were deposited by a dual-mode (radio frequency/microwave) reactor. A mixture of hydrogen and methane was used for deposition of DLC films. The film structure, thickness, roughness, refractive index of the films and plasma elements were investigated as a function of the radio frequency (RF) and microwave (MW) power, gas ratio and substrate substance. It was shown that by increasing the H₂ content, the refractive index grows to 2.63, the growth rate decreases to 10 (nm/min) and the surface roughness drops to 0.824 nm. Taking into consideration the RF power it was found that, as the power increases, the growth rate increases to 11.6 (nm/min), the variations of the refractive index and the roughness were continuously increasing, up to a certain limit of RF power. The Raman G-band peak position was less dependent on RF power for the glass substrate than that of the Si substrate and a converse tendency exists with increasing the hydrogen content. Adding MW plasma to the RF discharge (dual-mode) leads to an increase of the thickness and roughness of the films, which is attributed to the density enhancement of ions and radicals. Also, optical emission spectroscopy is used to study the plasma elements.     

Structural and mechanical properties of diamond-like carbon films deposited by an anode layer source

An anode layer source is a special ion gun, which can be fed with carbon precursors like acetylene to deposit hard and highly defect-free hydrogenated diamond-like carbon films at room temperature. The present study focuses on the influence of the process parameters — discharge voltage, process pressure and acetylene flow — on structure and mechanical properties of the deposited films. Raman spectra show that an increased discharge voltage yields decreased structural disorder, i.e. a lower C-C sp³ hybridised fraction of carbon atoms in the films. By an elevation of the discharge voltage from 1 to 3 kV the full width at half maximum of the G-band decreases from 194 ± 0.2 cm^− 1 to 183 ± 0.7 cm^− 1. Films deposited at the lowest discharge voltage show in accordance to the spectroscopic data the highest nanohardness (36 ± 1 GPa), stress (− 2.34 ± 0.2 GPa) and reduced elastic modulus (180 ± 4 GPa).