非平衡磁控溅射无氢DLC增透膜的研制

非平衡磁控溅射(UBMS)技术近年来得到了广泛地应用.采用该技术制备的类金刚石薄膜(DLC)具有许多独特的性质.本文利用正交实验方法,对非平衡磁控溅射技术制备无氢DLC膜增透膜进行了研究,得到了影响薄膜光学性能的主要因素和最佳的制备工艺.结果表明,非平衡磁控溅射制备的无氢DLC膜具有较宽的光谱透明区,锗基底单面沉积DLC膜,其峰值透射率达到61.4%,接近理论值.     

不同技术制备DLC膜的激光损伤特性研究

随着高能量大功率激光器的发展和激光元件的广泛应用,用于红外窗口表面增透保护的类金刚石薄膜(DLC)的抗激光损伤特性成为评价薄膜质量优劣的一个重要指标。然而,不同的制备方法和技术沉积的DLC薄膜具有各异的微观结构,从而具有不同的抗激光损伤特性。本文采用脉冲真空电弧(PVAD)和非平衡磁控溅射(UBMS)技术沉积了DLC膜,对两种DLC膜抗激光损伤特性进行了研究,测试结果表明,两种技术沉积的DLC薄膜激光损伤阈值分别0.6 J/cm2和0.3 J/cm2,PVAD技术比UBMS技术沉积的DLC薄膜具有更高的抗激光损伤阈值。基于实验研究了薄膜光学常数和表面形态,分析了两种技术制备DLC膜激光损伤特性差异的主要原因。结果表明,采用UBMS技术沉积的DLC膜具有较小的折射率和较大的消光系数,薄膜表面存在较多的疵病和缺陷,这些是其激光损伤阈值较低的主要原因。     

非平衡磁控溅射类金刚石薄膜的特性

非平衡磁控溅射(UBMS)结合了普通磁控溅射(MS)和离子束辅助沉积的优势,易于实现离子镀,近年来得到了广泛的应用.采用该技术制备的类金刚石薄膜(DLC)具有许多独特的性质.本文研究了非平衡磁控溅射技术制备DLC薄膜的光学、机械,电学和化学性能.研究表明,非平衡磁控溅射制备的DLC膜具有较宽的光谱透明区,且表面光滑、摩擦系数小、耐磨损、抗化学腐蚀,同时具有较高的电阻率和良好的稳定性.     

非平衡磁控溅射DLC薄膜应力研究

类金刚石（DLC）薄膜可用作红外增透保护膜,高的薄膜残余应力造成薄膜附着力下降是目前应用中存在的主要问题之一。本文从DLC薄膜作为红外增透保护膜的需求出发,采用非平衡磁控溅射技术生长DLC薄膜。实测了薄膜的残余应力,分析研究了薄膜残余应力在不同工艺条件下的变化情况。探讨了薄膜残余应力与薄膜厚度、光学透过率、离子能量、沉积速率以及能流密度之间的关系。研究结果表明,薄膜残余应力平衡值在0．9～2．2GPa之间,相应的单面镀膜样片的透过率在4μm波长处为69％～63％,随工艺的不同而变化。工艺优化后薄膜残余应力显著下降。硅基底上薄膜与基底剥离的力的临界值大于2160GPa．nm,最大薄膜厚度≥2400nm;锗基底上最大薄膜厚度≥2000nm,可以满足整个红外波段的需求。     

中频脉冲非平衡磁控溅射技术制备类金刚石膜的结构与性能

利用中频脉冲非平衡磁控溅射技术在载玻片上制备了类金刚石(DLC)薄膜,研究了沉积气压对薄膜厚度、微观结构、机械性能和光学性能的影响。厚度测试结果表明,DLC膜厚度随沉积气压的增加而增加。X射线光电子能谱测试结果表明,当沉积气压由0.18Pa增加到1.50Pa时,DLC薄膜中sp~3杂化碳含量随沉积气压的增加而减少。纳米压痕和椭偏仪测试结果表明,DLC膜的纳米硬度、折射率均随沉积气压的增加而减小。采用浅注入模型分析了沉积气压对薄膜生长和键合结构的影响。以上结果表明,沉积气压对DLC膜的厚度、sp~3杂化碳含量、机械与光学性能具有较大的影响。     

非平衡磁控溅射类金刚石碳膜的性能

用非平衡磁控溅射的方法在室温下制备了光滑、均匀、致密的类金刚石(DLC)薄膜,分析和研究了DLC膜的形貌、结构和摩擦特性.结果表明,靶工作电流对DLC膜的沉积有重要的影响.随着工作电流的增大,薄膜的沉积速率增大,薄膜中sp3键的含量增加.薄膜的摩擦系数随着工作电流的增加略有增大,在摩擦的初始阶段,摩擦系数较高,随着摩擦循环次数的增加,摩擦系数逐渐减小,并逐渐趋于稳定.     

类金刚石碳膜的红外特性研究

用射频等离子体方法分解甲烷，在Ge片上制备了类金刚石碳（DLC）膜。该膜折射率在2左右，具有较好的增透作用。双面镀DLC膜系统的红外透射比，随膜厚不同，其极大值在3．8～10．6μm范围内，在10．6μm处红外透射比达94．5％、镀制在直径为100mmGe基片上的DLC／Ge／DLC膜系、在10．6μm处，膜片中心的红外透射比为93．9％，距中心不同距离的5个点的红外透射比为91．1％，该膜系具有非常好的均匀性和红外增透性。通过计算获得了DLC膜的光学吸收系数曲线，该膜在3．8μm附近吸收系数为10cm-1；在10．6μm处吸收系数为600cm-1，并对该吸收曲线进行了讨论。     

退火对无氢钛掺杂类金刚石(Ti-DLC)膜结构及性能的影响

利用非平衡磁控溅射复合靶技术制备了一系列掺钛的无氢类金刚石(Ti-DIE)薄膜,并对薄膜的热稳定性能、机械性能、应力分布以及表面形貌进行了研究.实验结果表明:退火处理对Ti-DIE膜的性能具有重要影响.随着热处理温度的升高,成膜晶粒逐渐细化,电阻率上升但至一定值后趋于稳定.退火温度的升高,会促使薄膜应力逐渐减小,硬度变低,但其耐火温度可以达到600℃以上而不发生石墨化,这一结果为DLC膜在高温环境下的应用提供了一定思路.     

Si3N4球/DLC膜摩擦副在真空环境下的摩擦学行为研究

采用非平衡磁控溅射技术在高速钢基体上制备了类金刚石(DLC)膜。采用球盘式摩擦磨损试验机考察了DLC膜在大气和真空环境干摩擦条件下的摩擦学性能,并比较分析了GCr15钢球和Si3N4球不同摩擦配副对DLC膜的摩擦学性能。采用光学显微镜及扫描电镜观察了摩擦副的磨损表面形貌。研究结果表明:由于转移膜的形成Si3N4球/DLC膜摩擦副在大气下具有良好的摩擦学性能;而在真空条件下摩擦副易发生明显的粘着磨损,使摩擦系数、磨斑增加,磨损表面上存在着较多的片状磨屑和微米级颗粒。     

类金刚石薄膜的激光损伤特性及工艺优化

采用脉冲真空电弧沉积(PVAD)技术制备了类金刚石(DLC)薄膜,并对其抗激光损伤特性进行了研究,优化了制备工艺.对DLC薄膜激光损伤阈值(LIDT)的测试结果表明,随着厚度的增加,薄膜的LIDT开始呈下降趋势,当厚度达到100nm以上时,则趋于一个稳定值.正交实验结果的处理和分析表明,在所给定的工艺参数范围内,主回路电压是影响DLC膜抗激光损伤性能的最主要因素,基片温度、清洗时间和脉冲频率则影响较小.为得到较好的抗激光损伤能力,采用PVAD技术制备DLC薄膜的最佳工艺参数为:清洗时间20 min、基片温度150℃、脉冲频率5 Hz、主回路电压150 V.退火处理会使DLC薄膜的激光损伤阈值明显提高.     

Optimisation of diamond-like carbon films by unbalanced magnetron sputtering for infrared transmission enhancement

Diamond-like carbon (DLC) films have potential applications in infrared transmission enhancement. Reducing or eliminating mechanical stress and optical absorption of DLC is important in such applications because relatively thick films are necessary. In this work, DLC was deposited in an unbalanced magnetron sputtering (UBMS) system. Mechanical and optical properties of the DLC films were analysed. Thick DLC films were deposited which satisfied applications for the infrared windows at 3–5 and 8–10 μm. At optimised conditions, the stress in the DLC films decreased with increasing thickness, approaching 1 GPa. For single side DLC coated silicon substrate, about 69% transmittance was achieved at wavelengths near 5 μm, close to the theoretical value for non-absorbing DLC material. Other properties such as surface roughness, wetting angle, and stability were also studied, which showed that the DLC films produced in the UBMS system were excellent for infrared transmission enhancement applications in tough environments.     

Tribological properties of multilayer DLC/W-DLC films on Si

Multilayer films of diamond-like carbon (DLC) and tungsten-containing diamond-like carbon (W-DLC) films were deposited onto silicon wafers using radio frequency chemical vapor deposition (RFCVD) and a magnetron sputtering method. The W-DLC layer was deposited on the silicon wafer with less than 60 W magnetron output. The DLC layer was then deposited on the W-DLC layer.Surface morphology was investigated by atomic force microscopy and the film structure by transmission electron microscopy. Friction tests for multilayered films were performed in a nitrogen atmosphere at room temperature using a ball-on-disk tribometer. A conventional stainless steel ball was used for the test.The surface profiles seen by atomic force microscopy showed that round-shaped clusters of around 100 nm were observed in just the single W-DLC layer. These clusters were considered to be tungsten or tungsten-carbon composites. In the case of the DLC/W-DLC multilayered structure, the top DLC layer covered the W-DLC single layer and smoothed the surface of the W-DLC film.Friction tests demonstrated that the friction coefficient of the W-DLC single layer was above 0.6 and increased gradually as the number of cycle increased. The W-DLC films partially broke down during our measurements. However the DLC/W-DLC multilayer films showed stable friction properties and were observed for up to 100,000 cycles. Their friction coefficient was typically less than 0.1 at 10 cm/s rotating speed. The DLC/W-DLC multilayer films exhibited stable low friction properties in a long term test under a nitrogen atmosphere.     

CVD of hard DLC films in a radio frequency inductively coupled plasma source

Chemical vapor deposition (CVD) of hard diamond-like carbon (DLC) films on silicon (100) substrates from methane was successfully carried out using a radio frequency (r.f.) inductively coupled plasma source (ICPS). Different deposition parameters such as bias voltage, r.f. power, gas flow and pressure were involved. The structures of the films were characterized by Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The hardness of the DLC films was measured by a Knoop microhardness tester. The surface morphology of the films was characterized by atomic force microscope (AFM) and the surface roughness (R_a) was derived from the AFM data. The films are smooth with roughness less than 1.007 nm. Raman spectra shows that the films have typical diamond-like characteristics with a D line peak at 1331 cm⁻¹ and a G line peak at 1544 cm⁻¹, and the low intensity ratio of I_D/I_G indicate that the DLC films have a high ratio of sp³ to sp² bonding, which is also in accordance with the results of FTIR spectra. The films hardness can reach approximately 42 GPa at a comparatively low substrate bias voltage, which is much greater than that of DLC films deposited in a conventional r.f. capacitively coupled parallel-plate system. It is suggested that the high plasma density and the suitable deposition environment (such as the amount and ratio of hydrocarbon radicals to atomic or ionic hydrogen) obtained in the ICPS are important for depositing hard and high quality DLC films.     

Spectroscopic studies on DLC/TM (Cr,Ag, Ti,Ni) multilayers

The hydrogen-free diamond-like carbon (DLC) films with transition metal (TM = Cr, Ag, Ti, Ni) interlayer (bilayer and multilayer) were deposited on to stainless steel and silicon substrates using pulsed laser deposition technique. Secondary ion mass spectroscopy (SIMS) confirmed that the films were hydrogen free. Incorporation of chromium inter layer reduced the stress value by about 3 GPa as determined by micro Raman spectroscopy. Incorporation of the TM inter layer enhanced the photoluminescence (PL) intensity as compared to the monolithic DLC films. The optical band gap determined by spectroscopic ellipsometry for DLC/TM films was found to be in the range of 1.56–1.67 eV.     

Annealing effect on the structural, mechanical and electrical properties of titanium-doped diamond-like carbon films

Titanium-doped diamond-like carbon (Ti-doped DLC) films with a Ti content of 1.1 at.% were synthesized on a Si substrate by a process that involves filtered cathodic vacuum arc (FCVA) and metal vapor vacuum arc (MeVVA) systems. The effect of annealing temperature on the microstructure, surface roughness, hardness and electrical resistivity of the resulting films was evaluated in this study. The Raman spectra revealed that the degree of graphitization of the Ti-doped DLC thin films was increased from 25 to 600 °C and the microstructure of the films is converted to a nano-crystalline graphite structure. The resulting films maintain a smooth surface after the annealing process. The hardness of the Ti-doped DLC films increases as the annealing temperature increases up to 400 °C because the induced defects and the inter-atomic bonds are repaired after the annealing process. But the hardness decreases at the higher temperature due to the increase of number and size of the nano-crystalline graphitic domains. Since the degree of graphitization of the thin films increases, the electrical resistivity of the Ti-doped DLC thin films decreases from 0.038 to 0.006 Ω cm.     

轮胎模具无氢DLC涂层的制备及表征

为探究轮胎模具类金刚石(DLC)涂层的应用前景,提高模具表面的硬度和疏水性,按照模具加工工艺制备35钢基体试样,利用电弧离子镀在基体上沉积无氢DLC涂层,对涂层粗糙度、三维表面形貌、断面结构、元素组成及含量、Raman光谱、纳米硬度和疏水性进行了分析.结果表明:通过改变粗糙度可以改善涂层的疏水性,涂层疏水性随粗糙度增大而显著增加,水接触角最高可达96°,且涂层硬度可达30.3 GPa.无氢DLC涂层可满足轮胎模具耐磨性和易清洁的使用要求,为制造高性能轮胎模具提供了一种可行的工艺选择.     

等离子体源离子注入法制备类金刚石薄膜

用等离子体源注入(PSII)在Si(100)上制备类金刚石膜，放电气体采用CH4，用微波电子回旋共振(ECR)产生等离子体。将-20～-30kV的高压加在衬底上，来提高离子的能量。通过Raman光谱和FT-IR光谱检测了类金刚石膜的化学组成及状态，并对其机械性能和表面形貌进行了检测。结果显示，硅片硬度和摩擦因数得到了改善，用PSII能够制备出性能优良的膜，可以将其应用到微电子器件(MEMS)上去。