脉冲偏压电弧离子镀C-N-V薄膜的成分、结构与性能

用脉冲偏压电弧离子镀方法在硬质合金基体上制备了一系列不同成分的C-N-V薄膜.用X射线光电子能谱、激光Raman光谱、 X射线衍射(XRD)、透射电子显微镜(TEM)和纳米压痕等方法分别研究了薄膜的成分、结构与性能.Raman光谱,XRD和TEM结果表明,所制备的薄膜为在类金刚石(DLC)非晶基体上匹配有VN晶体的碳基复合薄膜.随V和N含量的增加,薄膜硬度与弹性模量先增加后下降,在N含量为204%,V含量为218%时薄膜硬度与弹性模量具有最大值,分别为368和5697 GPa,高于相同条件下制备的 关键词： C-N-V薄膜 类金刚石薄膜 纳米复合薄膜 电弧离子镀     

溅射功率对碳化硼薄膜组分与力学性能的影响

采用射频磁控溅射技术,在不同溅射功率条件下制备了碳化硼薄膜,并用X射线光电子能谱(XPS)和傅里叶变换红外吸收光谱(FT-IR)对碳化硼薄膜的组分进行了定量表征,分析了功率变化对碳化硼组分的影响。利用纳米压入仪通过连续刚度法(CSM)对碳化硼薄膜的硬度和模量等力学性能进行了分析。研究表明:随着功率的增大,硼与碳更易结合形成BC键,在功率增大到250 W时,BC键明显增多;在250 W时,硼与碳的原子分数比出现了最大值5.66;碳化硼薄膜的硬度与模量都随功率的增大呈现出先增大后减小的趋势,且在250 W时均出现了最大值,分别为28.22 GPa和314.62 GPa。     

高能氮离子轰击对四面体非晶碳膜的表面改性和摩擦系数影响的研究

利用过滤阴极真空电弧技术制备了sp³键含量不小于80%的四面体非晶碳(ta-C)膜.利用冷阴极潘宁离子源产生不同能量的氮离子对制备的ta-C薄膜进行轰击,通过X射线光电子能谱和原子力显微镜对薄膜表面结构与形貌进行分析研究.研究表明,随着氮离子的轰击能量的增大,薄膜中的CN键结构略有增大,形成了轻N掺杂;同时,在薄膜表层发生了sp³键结构向sp²键结构的转化;薄膜的表面粗糙度在经过氮离子轰击后从0.2 nm减小至0.18 nm,然后随着轰击能 关键词： 四面体非晶碳 X射线光电子能谱 摩擦系数     

脉冲高能量密度等离子体沉积(Ti,Al)N薄膜组织及其性能研究

利用脉冲高能量密度等离子体技术在室温条件下在45＃钢基材表面沉积了高硬度耐腐蚀(Ti, Al)N薄膜. 利用扫描电子显微镜、X射线衍射、X射线光电子能谱、俄歇电子能谱分析了薄膜的显微组织.利用纳米压痕仪测试了薄膜的纳米硬度.测试了薄膜在05mol/L H2SO4水溶液中的耐蚀性. 测试结果表明：薄膜主要组成相为(Ti, Al)N，同时含有少量的AlN,薄膜的纳米硬度高达26 GPa,薄膜具有良好的耐蚀性，与1Cr18Ni9Ti奥氏体不锈钢相比，耐蚀性提高了一个数量级. 关键词： 脉冲高能量密度等离子体 薄膜 纳米硬度 耐蚀性     

辉光放电等离子体辅助XeCl准分子激光溅射沉积碳氮薄膜

利用直流辉光放电等离子体辅助的脉冲激光沉积技术在Si衬底上生长了碳氮薄膜.通过扫描电子显微镜、X射线衍射、X射线光电子能谱、俄歇电子能谱等多种手段,对薄膜的形貌、成分、晶体结构、价键状态等特性进行了分析和确定.结果表明,沉积薄膜为含有非晶SiN和晶态氮化碳颗粒结构,晶态成分呈多晶态,主要为α-C₃N₄相、β-C₃N₄相,晶粒大小为40—60nm.碳氮之间主要以C-N非极性共价键形式相结合. 关键词： 脉冲激光沉积 直流辉光放电 碳氮薄膜     

Be薄膜应力的X射线掠入射侧倾法分析

由于铍薄膜极易被X射线穿透, 传统的几何模式下很难获得有效的X射线衍射应力分析结果. 本文采用掠入射侧倾法分析SiO₂基底上Be薄膜残余应力, 相比其他衍射几何方法, 提高了衍射的信噪比, 获得的薄膜应力拟合曲线线形较好. 对Be薄膜的不同晶面分析, 残余应力结果相同, 表明其力学性质各向同性; 利用不同掠入射角下X射线的穿透深度不同, 获得应力在深度方向上的分布; 由薄膜面内不同方向的残余应力相同, 确定薄膜处于等双轴应力状态. 关键词： Be薄膜 X射线衍射 应力     

微波ECR磁控溅射制备SiNx薄膜的XPS结构研究

利用微波电子回旋共振等离子体增强非平衡磁控溅射法在不同N2流量下制备无氢SiNx薄膜.通过X光电子能谱、纳米硬度仪等表征技术,研究了不同N2流量下制备的SiNx薄膜的化学键结构、化学键含量、元素配比及各元素沿深度分布.研究结果表明,N2流量是影响SiNx薄膜化学键结构、元素配比、元素延深度分布等性质的主要因素.在N2流量为1 sccm的条件下制备的SiNx薄膜呈富Si态;在N2流量为2 sccm的条件下制备的SiNx薄膜中Si-N键含量最高,可达到94.8%,化学吸附主要发生在薄膜表面,同时薄膜具有较好的机械性能,硬度值可达到22.9 GPa;在N2流量为20 sccm条件下制备的SiNx薄膜,薄膜表面含有46.8%的N-Si-O键及18.6%的Si-O键结构,薄膜内部含有36.8%的N-Si-O键及12.5%的Si-O键结构,表明薄膜结构疏松,在空气中易被氧化,化学吸附在薄膜表面及内部同时发生,因此薄膜具有较差的机械性能,硬度值仅为12 GPa.     

非晶Ni88P12合金薄膜的表面形貌特征与晶化行为的研究

采用化学镀的方法在363K和p型Si（100）衬底上制得非晶Ni₈₈P₁₂合金薄膜．利用X射线衍射、X射线光电子能谱、扫描隧道显微镜和原子力显微镜对非晶合金薄膜及其经处理后形成的氧化态、还原态和晶态的结构、组分和表面的形貌特征作了研究，并对它的晶化行为作了初步探讨．结果表明，非晶合金薄膜是由纳米级微粒聚集成微米级颗粒组成；在低于晶化温度条件下经氧化和还原处理后的薄膜表面晶化；在晶化过程中，合金薄膜的非晶纳米微粒转变为微晶后长大成晶粒，其表面结构光滑平坦，几何边界 关键词：     

CHN薄膜的制备方法与工艺研究

 采用空心阴极等离子化学气相沉积方法，以NH₃/H₂的混合气体及CH4气体为原料反应气体，成功地制备了非晶的CHN薄膜，研究了CHN薄膜的沉积速率与直流电压及反应气体流量的关系。同时用X射线光电子能谱(XPS)确定了不同条件下薄膜中N原子的百分比，用原子力显微镜(AFM)对薄膜的表面粗糙度及表面形貌进行了测量和表征。结果表明：薄膜中N原子的百分比最大为12%，薄膜的表面结构光滑、致密，表面粗糙度小于1 nm。     

308nm激光作用下V2O5非晶薄膜的变异

研究了在308nm准分子激光辐照下，V₂O₅非晶薄膜性质的变化-利用X射线衍射、X射线光电子能谱及扫描电子显微镜等多种测试方法进行了分析比较，确定V₂O₅非晶薄膜性质的变化是由于高功率密度的准分子激光作用，造成V₂O₅薄膜的快速升温熔化和快速冷凝重构，使其中的氧产生缺位，引起化学配比偏离所致- 关键词：     

Fabrication and characterization of freestanding ultrathin diamond-like carbon targets for high-intensity laser applications

Here, we report the fabrication of diamond-like carbon (DLC) thin films using pulsed laser deposition (PLD). PLD is a well-established technique for deposition of high-quality DLC thin films. Carbon tape target was ablated using a KrF (248 nm, 25 ns, 20 Hz) excimer laser to deposit DLC films on soap-coated substrates. A laser fluence between 8.5 and 14 J/cm² and a target to substrate distance of 10 cm was used. These films were then released from substrates to obtain freestanding DLC thin foils. Foil thicknesses from 20 to 200 nm were deposited using this technique to obtain freestanding targets of up to 1-inch square area. Typically, 100-nm-thick freestanding DLC films were characterized using different techniques such as AFM, XPS, and nano-indentation. AFM was used to obtain the film surface roughness of 9 nm rms of the released film. XPS was utilized to obtain 74 % sp², 23 % sp³, and 3 % C–O bond components. Nano-indentation was used to characterize the film hardness of 10 GPa and Young’s modulus of 110 GPa. Damage threshold properties of the DLC foils were studied (1,064 nm, 6 ns) and found to be 7 × 10¹⁰ W/cm² peak intensity for our best ultrathin DLC foils.     

Adjusting chemical bonding of hard amorphous CSixNy thin films by N*-plasma-assisted pulsed laser deposition

Hard amorphous carbon silicon nitride thin films have been grown by pulsed laser deposition (PLD) of various carbon silicon nitride targets by using an additional nitrogen RF plasma source on [100] oriented silicon substrates at room temperature. The influence of the number of laser shots per target site on the growth rate and film surface morphology was studied. Up to about 30 at. % nitrogen and up to 20 at. % silicon were found in the films by Rutherford backscattering spectroscopy (RBS) and X-ray photoelectron spectroscopy (XPS). The XPS of the films showed a clear correlation of binding energy to the variation of PLD parameters. The films show a universal hardness value up to 23 GPa (reference value for silicon substrate 14 GPa) in dependence on target composition and PLD parameters. The results emphasise the possibility of variation of chemical bonding and corresponding properties, such as nanohardness, of amorphous CSi_xN_y thin films by the plasma-assisted PLD process.     

Structure and mechanical properties of low stress tetrahedral amorphous carbon films prepared by pulsed laser deposition

Tetrahedral amorphous carbon films have been produced by pulsed laser deposition, at a wavelength of 248 nm, ablating highly oriented pyrolytic graphite at room temperature, in a 10^-2 Pa vacuum, at fluences ranging between 0.5 and 35 Jcm^-2. Both (100) Si wafers and wafers covered with a SiC polycrystalline interlayer were used as substrates. Film structure was investigated by Raman spectroscopy at different excitation wavelength from 633 nm to 229 nm and by transmission Electron Energy Loss Spectroscopy. The films, which are hydrogen-free, as shown by Fourier Transform Infrared Spectroscopy, undergo a transition from mainly disordered graphitic to up to 80% tetrahedral amorphous carbon (ta-C) above a threshold laser fluence of 5 J cm^-2. By X-ray reflectivity roughness, density and cross-sectional layering of selected samples were studied. Film hardness as high as 70 GPa was obtained by nanoindentation on films deposited with the SiC interlayer. By scratch test film adhesion and friction coefficients between 0.06 and 0.11 were measured. By profilometry we obtained residual stress values not higher than 2 GPa in as-deposited 80% sp³ ta-C films. Received 25 June 2001     

TiCN thin films grown by reactive crossed beam pulsed laser deposition

In this work, we used a crossed plasma configuration where the ablation of two different targets in a reactive atmosphere was performed to prepare nanocrystalline thin films of ternary compounds. In order to assess this alternative deposition configuration, titanium carbonitride (TiCN) thin films were deposited. Two crossed plasmas were produced by simultaneously ablating titanium and graphite targets in an Ar/N₂ atmosphere. Films were deposited at room temperature onto Si (100) and AISI 4140 steel substrates whilst keeping the ablation conditions of the Ti target constant. By varying the laser fluence on the carbon target it was possible to study the effect of the carbon plasma on the characteristics of the deposited TiCN films. The structure and composition of the films were analyzed by X-ray Diffraction, Raman Spectroscopy and non-Rutherford Backscattering Spectroscopy. The hardness and elastic modulus of the films was also measured by nanoindentation. In general, the experimental results showed that the TiCN thin films were highly oriented in the (111) crystallographic direction with crystallite sizes as small as 6.0 nm. It was found that the hardness increased as the laser fluence was increased, reaching a maximum value of about 33 GPa and an elastic modulus of 244 GPa. With the proposed configuration, the carbon content could be easily varied from 42 to 5 at.% by changing the laser fluence on the carbon target.     

Chemical composition of ZrC thin films grown by pulsed laser deposition

ZrC films were grown on (1 0 0) Si substrates by the pulsed laser deposition (PLD) technique using a KrF excimer laser working at 40 Hz. The nominal substrate temperature during depositions was set at 300 °C and the cooling rate was 5 °C/min. X-ray diffraction investigations showed that films deposited under residual vacuum or under 2 × 10⁻³ Pa of CH₄ atmosphere were crystalline, exhibiting a (2 0 0)-axis texture, while those deposited under 2 × 10⁻² Pa of CH₄ atmosphere were found to be equiaxed and with smaller grain size. The surface elemental composition of as-deposited films, analyzed by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS), showed the usual high oxygen contamination of carbides. Once the topmost 2-4 nm region was removed, the oxygen concentration rapidly decreased, down to around 3-8% only in bulk. Simulations of the X-ray reflectivity (XRR) curves indicated a smooth surface morphology, with roughness values below 1 nm (rms) and films density values of around 6.30-6.45 g/cm³, very close to the bulk density. The growth rate, estimated from thickness measurements by XRR was around 8.25 nm/min. Nanoindentation results showed for the best quality ZrC films a hardness of 27.6 GPa and a reduced modulus of 228 GPa.     

Characteristics of ZrC/ZrN and ZrC/TiN multilayers grown by pulsed laser deposition

ZrC/ZrN and ZrC/TiN multilayers were grown on (1 0 0) Si substrates at 300 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser. X-ray diffraction investigations showed that films were crystalline, the strain and grain size depending on the nature and pressure of the gas used during deposition. The elemental composition, analyzed by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS), showed that films contained a low level of oxygen contamination. Simulations of the X-ray reflectivity (XRR) curves acquired from films indicated a smooth surface morphology, with roughness below 1 nm (rms) and densities very close to bulk values.Nanoindentation results showed that the ZrC/ZrN and ZrC/TiN multilayer samples exhibited hardness values between 30 and 33 GPa, slightly higher than the values of 28-30 GPa measured for pure ZrC, TiN and ZrN films.     

Fabrication of diamond-like carbon thin films by femtosecond laser ablation of frozen acetone

Diamond-like carbon (DLC) thin films were fabricated by the ablation of frozen acetone with a 790 nm, 130 fs Ti:sapphire laser. Compared to a solid carbon target, frozen acetone could significantly reduce the number of fragments mixed into the films. The optical and mechanical properties of the fabricated DLC films were determined when the laser fluence was varied from 3 to 470 J/cm². With the increase in laser fluence, the films tinged with brown and the optical bandgap of the films decreased from 2.0 to 1.2 eV. Also, the refractive index and hardness of the films increased from 1.75 to 1.99 and from 10 to 16 GPa, respectively. The sp³ content was not changed even if the laser fluence was varied. The change in properties resulted from the hydrogen content of the films. PACS 81.05.Uw; 81.15.Fg     

Critical role of laser wavelength on carbon films grown by PLD of graphite

The structure of thin films deposited by pulsed laser ablation (PLD) is strongly dependent on experimental conditions, like laser wavelength and fluence, substrate temperature and pressure. Depending on these parameters we obtained various kinds of carbon materials varying from dense, mainly tetrahedral amorphous carbon (ta-C), to less compact vertically oriented graphene nano-particles. Thin carbon films were grown by PLD on n-Si 〈100〉 substrates, at temperatures ranging from RT to 800°C, from a rotating graphite target operating in vacuum. The laser ablation of the graphite target was performed by a UV pulsed ArF excimer laser (λ=193 nm) and a pulsed Nd:YAG laser, operating in the near IR (λ=1064 nm). The film structure and texturing, characterised by X-ray diffraction analysis, performed at grazing incidence (GI-XRD), and the film density, evaluated by X-ray reflectivity measurements, are strongly affected both by laser wavelength and fluence and by substrate temperature. Micro-Raman and GI-XRD analysis established the progressive formation of aromatic clusters and cluster condensation into vertically oriented nano-sized graphene structures as a direct function of increasing laser wavelength and deposition temperature. The film density, negatively affected by substrate temperature and laser wavelength and fluence, in turn, results in a porous bulk configuration and a high macroscopic surface roughness as shown by SEM characterisation. These structural property modifications induce a relevant variation also on the emission properties of carbon nano-structures, as evidenced by field emission measurements. This work is dedicated to our friend Giorgio who passed away 20th August.     

Synthesis and characterization of superhard Ti-Si-N films obtained in an inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement

Using a novel inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement system, Ti-Si-N films were prepared on single-crystal silicon wafer substrates by sputtering Ti and Si (5 at.%:1 at.%) alloyed target in argon/nitrogen plasma. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), atomic force microscopy (AFM) and Nano Indenter XP tester were employed to characterize nanostructure and performances of the films. These films were essentially composed of TiN nanocrystallites embedded in an amorphous Si₃N₄ matrix with maximum hardness value of 44 GPa. Experimental results showed that the film hardness was mainly dependent on the TiN crystallite size and preferred orientation, which could be tailored by the adjustment of the N₂/Ar ratio. When the N₂/Ar ratio was 3, the film possessed the minimum TiN size of 10.5 nm and the maximum hardness of 44 GPa.     

Effect of laser fluence on the deposition and hardnessof boron carbide thin films

We deposited amorphous thin films of boron carbide by pulsed laser deposition using a B₄C target at room temperature. As the laser fluence increased from 1 to 3 J/cm², the number of 0.25–5 μm particulates embedded in the films decreased, and the B/C atomic ratio of the films increased from 1.8 to 3.2. The arrival of melt droplets, atoms, and small molecular species depending on laser fluence appeared to be involved in the film formation. In addition, with increasing fluence the nanoindentation hardness of the films increased from 14 to 32 GPa. We believe that the dominant factor in the observed increase in the films’ hardness is the arrival of highly energetic ions and atoms that results in the formation of denser films. Received: 23 March 2001 / Accepted: 1 July 2001 / Published online: 2 October 2001