异质a-C:H/a-C:H:F配副的摩擦学行为研究

目的 研究F元素掺杂非晶碳基薄膜与a-C:H薄膜摩擦配副的摩擦学行为机制。方法 利用PECVD法在Si基底上制备a-C:H:F薄膜,与直径为6.0 mm的a-C:H薄膜摩擦对偶球组成摩擦配副体系,使用往复模式的CSM TRB 3摩擦机研究a-C:H:F薄膜的摩擦学特性,频率为5 Hz,滑动总次数为9 000,外加载荷分别为2、4、6、8、10N。通过纳米硬度、X射线光电子能谱、傅里叶红外光谱、激光共聚焦拉曼光谱、场发射扫描电镜及CSM摩擦试验机等,分别评价a-C:H:F薄膜的结构、表面形貌、力学性能、摩擦学性能等。结果 在干摩擦环境下,随着载荷的增加,a-C:H:F薄膜的摩擦因数逐渐降低,平稳后摩擦因数低至0.018。通过掺杂F元素,一方面促进了薄膜的sp²-C杂化,另一方面增大了薄膜的无序度。F元素具有钝化薄膜表面和静电排斥的作用,使得a-C:H:F薄膜具有较低的摩擦因数和磨损率。结论 采用PECVD方法制备的a-C:H:F薄膜具有更好的减摩降损能力。     

a-C：F：H films prepared by PECVD

Fluorinated amorphous hydrogenated a-C:F:H carbon thin films were deposited using radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) reactor with CF4 and CH4 as source gases and were an-nealed in a N2 atmosphere. The properties of these films were evaluated by FTIR spectrometry, UV-VIS spectro-photometry and single-wavelength spectroscopic ellipsometry. A correspondence relativity connection between the deposition rate and technology was found. The chemical bonding structures and the content of CHx and CFx in the films are transformed and the optical band gap decreases monotonically with increasing temperature after annealing.The dielectric constant is increased with decreasing content of F in the films and the optical band gap is decreased with decreasing the content of H in the film.     

a-C∶F∶H films prepared by PECVD

1　INTRODUCTIONRecentadvancesinultralargescaleintegrationdevices(ULSI)haveledtoaneedfornewintercon netionsmaterialswithlowresistivityandinterlayermaterialswithlowdielectricconstanttoreducetheinterconnetiondelay ,interfere ,noiseandwastagecausedbyparasiticcapacitance .ReplacingAlintradi tionalAl/SiO2 systemwithCu ,ithasreachedaunanimousagreement .MaterialsunderresearchtoreplaceSiO2 mainlycontainPTFE ,SiOF ,F PIanda C∶F∶H .PTFE(κ≈2 .0 )andSiOF(κ≈3.0～3.5 )havelowdielectric…     

低温等离子体增强化学气相沉积纳米结构碳化钨薄膜

采用氟化钨（WF6）和甲烷为前驱体气体，以氩气为载气，在氢气氛下，采用等离子体增强化学气相沉积（PECVD）方法在低温下制备具有纳米结构的碳化钨薄膜。采用SEM、AFM、XRD、EDS等方法表征了碳化钨薄膜的形貌、晶体结构和化学组成，表明基体温度在450℃，甲烷与氟化钨气体流量比为10时得到的碳化钨薄膜是以直径为Ф40～80nm，高度为150～200nm的圆柱状的纳米晶粒聚合体组成。探讨了低温制备纳米结构碳化钨薄膜的机理，分析了基体温度对薄膜物相和微观结构的影响。     

离子源功率对a-C:H(Al)薄膜结构及性能的影响

目的研究离子源功率对a-C:H(Al)薄膜结构及性能的影响。方法采用阳极离子源离化CH_4气体,中频磁控溅射Al靶,通过改变离子源功率,在n(100)型单晶硅及16Mn Cr5钢基体上沉积a-C:H(Al)薄膜。利用扫描电镜、维氏显微硬度计、摩擦磨损试验机和表面轮廓仪等设备对a-C:H(Al)薄膜的结构及性能进行表征。结果薄膜的硬度均在1000HV以上。摩擦系数较低,为0.05~0.15。离子源功率为450 W时,薄膜摩擦系数和结合力均出现了最优值,分别为0.05和21.46 N。离子源功率在550 W时,磨损率达到最低值,为3.59×10~(-7) mm~3/(N·m)。结论离子源功率较低时,薄膜表面较疏松,随着离子源功率的增加,薄膜逐渐趋于平整致密。随离子源功率的增加,薄膜的硬度增大,薄膜的结合力先增大后减小,而薄膜的摩擦系数先减小后增大,磨损宽度减小,磨损深度降低,磨损率减小。     

多晶硅薄膜的工艺研究

研究了制备性能优良非晶硅薄膜的工艺参数，对薄膜进行高温退火得到多晶硅薄膜。用X射线衍射仪(xRD)和扫描电镜(SEM)，观察薄膜的结晶情况以及晶粒的大小。结果表明：退火温度越高，退火时间越长，得到多晶硅薄膜的比例越高，晶粒也相对较大；薄膜在(111)方向上优先结晶，晶粒大小可以达到1μm，与理论值做了比较。     

HWCVD与RF-PECVD复合技术制备微晶硅薄膜的性能*

采用热丝化学气相沉积(HWCVD)和射频等离子体化学气相沉积(RF-PECVD)相结合的技术,在普通载玻片和聚酰亚胺衬底上沉积制备微晶硅薄膜。系统考查了热丝到衬底的距离对沉积薄膜结构和性能的影响规律,用拉曼光谱仪、X-射线衍射仪(XRD)、紫外可见光纤光谱仪对薄膜的晶化率、微观结构和光学性能进行研究。结果表明:薄膜沉积速率最高可达到0.73nm/s,晶化率和禁带宽度分别可以在0%～78%和0.86～1.28eV变化,射频等离子体的引入有助于多晶硅薄膜的(220)择优生长,HWCVD的引入有助于薄膜晶化。     

退火气氛对SnO_2:F薄膜low-e性能的影响（英文）

SiO_2:F薄膜作为low-e玻璃的功能层材料,广泛应用于节能镀膜玻璃。对帮化学气相沉积法在玻璃表面沉积的约250 nm厚的SiO_2:F薄膜进行不同气氛的退火处理。结果发现,薄膜的电学、光学性能在氦气和空气两种不同的退火气氛下会有显著的变化。SiO_2:F薄膜的Low-e性能经过空气中高温退火下降明显。但在空气中退火后,再在氮气保护下退火,性能会有所恢复。对该现象的机理也进行了研究。     

低功率MPCVD制备金刚石薄膜

通过微波等离子体化学气相沉积(MPCVD)法,以CH4/H2为气源,合成高质量金刚石薄膜,在150 W低微波功率下,从衬底预处理方法、沉积气压、流量比等方面对制备高质量金刚石薄膜的工艺参数进行研究.结果表明:高流量比不利于金刚石颗粒的粒径控制,二次形核的存在可以获得近纳米级颗粒尺寸的金刚石薄膜;较大的沉积气压有利于制备...     

等离子体化学气相沉积超硬薄膜

本文简述了PCVD技术的原理、特性、设备。并对其制备的TiN、TiC、Ti(C_xN_y)超硬膜进行了显微硬度和化学成份等分析,最后介绍了该项技术在冷挤压冲头上的应用实例。     

Influence of nitrogen doping on thermal stability of fluorinated amorphous carbon thin films

Nitrogen doping fluorinated amorphous carbon （α-C ： F） films were deposited using radio frequency plasma enhanced chemical vapor deposition （RF-PECVD） and annealed in Ar environment in order to investigate their thermal stability. Surface morphology and the thickness of the films before and after annealing were characterized by AFM and ellipsometer. Raman spectra and FHR were used to analyze the chemical structure of the films. The results show that the surface of the films becomes more homogeneous either by the addition of N2 or after annealing. Deposition rate of the films increases a little at first and then decreases sharply with the increase of N2 source gas flux. It is also found that the fraction of aromatic rings structure increases and the thermal stability of the films is strengthened with the increase of N2 flux. Nitrogen doping is a feasible approach to improve the thermal stability of α-C ： F films.     

Electrical properties of amorphous carbon films

Aromatic polyimide films, Upilex S partially carbonized between 700°C and 1000°C. Electrical conductivity is higher at higher temperatures. The electrical conductivity s could be expresses as s = s_o exp (−E/kT), where k is the Boltzmann constant, t is the absolute measuring temperature. s_o and E are found to be 4 × 10⁻¹ Ω⁻¹ m⁻¹ and 0.02eB, respectively. The experimental data show that the Hall coefficient R is negative, and this implies that the carriers are negatively charged, i.e. electrons. The specimens are n-type semiconductors. The carrier density η is given by η = 1/(|e|R) and the mobility μ is μ is s/(η|e|), where |e| is the absolute value of the electron charge and s is the electrical conductivity. Fitting the data, η = A₁ exp (−E₁/κT) and μ = A₂ exp (E₂/κT). E₁ and E₂ depend on carbonized temperature. The polyimide films are not completely carbonized but partially carbonized at 700°C. The partially carbonized polyimide is an n type donor. It is concluded that the “impurity level” lies about 0.36eV below the conduction band.     

Effects of nitrogen content on structure and electrical properties of nitrogen-doped fluorinated diamond-like carbon films

Nitrogen-doped fluorinated diamond-like carbon (FN-DLC) films were prepared on single crystal silicon substrate by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) under different deposited conditions with CF₄, CH₄ and nitrogen as source gases. The influence of nitrogen content on the structure and electrical properties of the films was studied. The films were investigated in terms of surface morphology, microstructure, chemical composition and electrical properties. Atomic force microscopy (AFM) results revealed that the surface morphology of the films became smooth due to doping nitrogen. Fourier transform infrared absorption spectrometry (FTIR) results showed that amouts of C=N and C

N bonds increased gradually with increasing nitrogen partial pressure r (r=p(N₂)/p(N₂+CF₄+CH₄)). Gaussian fit results of C 1s and N 1s in X-ray photoelectron spectra (XPS) showed that the incorporation of nitrogen presented mainly in the forms of β-C₃N₄ and a-CN_x (x=1, 2, 3) in the films. The current?voltage (I?V) measurement results showed that the electrical conductivity of the films increased with increasing nitrogen content.     

Studies of nanostructured copper/hydrogenated amorphous carbon multilayer films

Nanostructured copper/hydrogenated amorphous carbon (a-C:H) multilayer grown in a low base vacuum (1 × 10⁻³ Torr) system combining plasma-enhanced chemical vapor deposition and sputtering techniques. These nanostructured multilayer were found to exhibit improved electrical, optical, surface and structural properties, compared to that of monolayer a-C:H films. The residual stresses of such multilayer structure were found well below 1 GPa. Scanning electron microscopy and atomic force microscopy results revealed a nanostructured surface morphology and low surface roughnesses values. X-ray photoelectron spectroscopy, secondary ion mass spectroscopy and energy dispersive X-ray analysis confirmed a very small amount of copper in these films. These structures exhibited very high optical transparency in the near infrared region (∼90%) and the optical band gap varied from 1.35 to 1.7 eV. It was noticed that the temperature dependent conductivity improved due to the presence of both copper and the nano-structured morphology.     

Corrosion protection ability of plasma-deposited amorphous hydrogenated carbon and fluorocarbon films

Hydrogenated diamond-like carbon and fluorocarbon films, deposited in a radio-frequency (rf) plasma reactor, have high chemical inertness and high electrical resistivity. These films, deposited on aluminum and type 301 stainless steel substrates at several rf power and feed gas flow rates using different gas phase precursors, were characterized for their pinhole density and stability with exposure to 0.6 M NaCl and 0.1 M NaCl and 0.1 M Na₂SO₄ solutions using electrochemical impedance spectroscopy and potentiostatic techniques, respectively. The results from electrochemical characterizations with salt water exposure indicated that films with high effective pore resistances (>10⁸ Ω · cm²)* and high stability with exposure (<10% changes in capacitance values) can be obtained over a narrow range of process conditions and gas phase compositions.     

The energy influx during plasma deposition of amorphous hydrogenated carbon films

The integral energy influx from the plasma to the substrate was determined for amorphous hydrogenated carbon (a-C:H) film deposition by magnetron sputtering and in an electron cyclotron resonance (ECR) discharge. The measurements, for which a thermal probe was designed, are based on time evolution of the substrate temperature during the deposition process. The different contributions to the integral energy influx were estimated by model calculations on the basis of assumptions for the kinetic energy of the charge carriers, their recombination, and film condensation. The energy influx during deposition in the CH₄-ECR plasma, which is in the range of 0.5–2 J s⁻¹, is predominantly determined by ions and chemical reactions, while the energy influx in magnetron sputtering, being in the range of 0.2–1.2 J s⁻¹, is mainly determined by fast neutrals and target radiation. The present results emphasise that the energy influx is a key parameter in thin film deposition and is important for comparison and scaling-up of different plasma process systems.     

Effect of substrate bias in amorphous carbon films having embedded nanocrystallites

The effect of substrate bias on the structural, morphological, electrical and mechanical properties of amorphous carbon (a―C) films having embedded nanocrystallites deposited by filtered cathodic jet carbon arc technique has been investigated. X-ray diffraction exhibits predominantly an amorphous nature of the film. High resolution transmission electron microscope investigations reveal largely an amorphous structure. However, an ultra-fine nanograined microstructure with the average grain size between 20 and 50 nm was observed throughout the entire film and the majority of the individual grains were single crystallites with the preferred interplanar spacing of about 0.2 nm. All the parameters evaluated were seen to depend strongly on the negative substrate bias and exhibit maxima or minima in the properties of the films deposited at − 150 V substrate bias. These a-C films having embedded nanocrystallites act as hard coating materials.     

Annealing effects in Ag-doped amorphous carbon films deposited by dc magnetron sputtering

Thin carbon films containing about 11 at.% Ag were deposited by dc magnetron sputtering of composite graphite/silver target. The stability of film microstructure upon annealing at 600 °C in a vacuum has been studied by transmission electron microscopy and electron diffraction. The as-deposited C/Ag films consisted of silver nanoparticles distributed in an amorphous carbon matrix. Upon annealing, the tendency was revealed towards coalescence within the set of particles, i.e. increase in the particle average diameter and decrease in the density of particles with time. The above changes occurred faster than it is predicted by the theories for three-dimensional and two-dimensional diffusion coalescence. The direct collisions and fusion of particles along with the diffusion transport of Ag atoms is suggested to cause the above effect.     

Effect of nitrogen on tribological properties of amorphous carbon films alloyed with titanium

The article reports on the dependency of friction and wear of a-(Ti,C,N) films on the nitrogen content. The amount of nitrogen N in the film was controlled by partial pressure of nitrogen p_N2 in the Ar + N₂ sputtering gas mixture. It is shown that the incorporation of N in the film results in the increase of (i) the coefficient of friction μ (increases from 0.12 to 0.37), (ii) the coefficient of wear k (increases from 0.16 × 10^?6 to 0.93 × 10^?6 mm³/N m) and the decrease of (i) the film hardness H, (ii) effective Young's modulus E^?, (iii) the elastic recovery W_e of film and (iv) the ratio H/E^?. The changes of μ and k of the a-(Ti,C,N) film correlate well with changes of the film mechanical properties (H and E^?) and its mechanical behavior (W_e, H/E^? and the ratio H³/E^?2) characterizing the film resistance to plastic deformation.     

Time and temperature-dependent changes in the structural properties of tetrahedral amorphous carbon films

The time and temperature-dependent changes in the structural properties of tetrahedral amorphous carbon (ta-C) films were accessed continuously by Raman spectroscopy. It has been found that a film of 70-nm thickness remains structurally stable after annealing in air at up to 300°C for 4 h. Although some degree of graphitization was observed on a film annealed at 400°C, the film begins to oxidize and lose thickness only after annealing at 500°C for more than 2 h. This reflects the high thermal stability of the films. In general, annealing results in a narrowing and an upshifting of the G-band together with an increase in the I_D/I_G ratio. Most of these changes were observed during the first 2 h of annealing, after which the structure of the film appears to stabilize, with the exception at 500°C in which the film deteriorates further as oxidation occurs. It was also observed that thin film has better thermal stability against graphitization than thick film.