离子束增强沉积制备碳化硼及C-B-Ti化合物薄膜的结构与力学性能的研究

利用离子束共混制备具有高硬度、高熔点及良好化学稳定性的C，B化合物（如：碳化硼、硼化钛等），对于采用离子束增强沉积技术进行材料表面改性有重要意义。利用对烧结碳化硼化合物靶进行溅射沉积，同时利用不同能量的Ar 进行轰击的方法，制备了碳化硼及碳、硼、钛混合薄膜，并对它们的结构与力学性能进行了研究。     

等离子体辅助脉冲激光沉积和原位掺杂方法制备稀土掺杂GaN薄膜

利用基于双激光束双靶共烧蚀的等离子体辅助脉冲激光沉积的化合物薄膜沉积和原位掺杂方法,制备了稀土Er掺杂和Pr掺杂的GaN薄膜.基质膜层中的Ga和N化合成键形成GaN,其组织结构为六角CaN相,膜层具有良好的可见光至近红外的透光性能.改变两激光束的重复频率比可以获得0.2%~5%不等的Er或Pr的掺杂浓度,GaN基质的化学成键、组织结构和透光性能没有因稀土的掺入而发生明显的变化.     

离子束辅助磁控溅射制备类石墨碳膜的结构与性能研究

采用离子束辅助磁控溅射技术(IBMSD)制备了高硬度、低电阻率的类石墨碳膜(GLC), 用TEM和XRD考察其组成相, 用XPS、FTIR和电阻率间接确定其碳键结构, 并测定了不同气体和离子能 量辅助轰击下制备的几组薄膜的沉积速率、成分、硬度和粗糙度等. 结果表明: 采用IBMSD制备的GLC是一种以sp²键为主的非晶硬质碳膜. CH₄辅助轰击较Ar有利于提高沉积速率. 辅助轰击能量的增大使薄膜表面粗糙度先减小后增大, 硬度的变化一定程度上与粗糙度相关.     

低能氮离子束辅助真空电弧沉积Zr-Cu-N薄膜的研究

利用等离子体辅助真空电弧沉积技术,在高速钢和单晶硅基体上制备Zr-Cu-N复合薄膜.采用X射线衍射仪(XRD)、扫描电镜(SEM)和超微显微硬度计研究了低能氮离子束流对Zr-Cu-N涂层结构、表面形貌和硬度的影响.结果表明:用低能氮离子束辅助真空电弧沉积Zr-Cu-N膜,ZrN结构在(111)晶面出现择优取向,并对Zr-Cu-N膜层有一定的强化作用,膜层表现出较高的显微硬度和转好的耐磨性能.     

硼碳氮薄膜的脉冲激光沉积及其光学性能

采用脉冲激光沉积技术,在Si(100)和石英基片上制备了硼碳氮薄膜(BCN)。利用X射线衍射(XRD),傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)和紫外-可见分光光度计对BCN薄膜进行了表征,研究了激光能量密度对BCN薄膜沉积速率、组分、结构和光学性能的影响。FTIR和XPS分析结果表明BCN薄膜中包含B-C,C-N和N-B化学键,说明实现了B、C和N的原子级化合。当激光能量密度从1 J/cm2增加到6 J/cm2时,BCN薄膜的沉积速率加快,N含量由7.2%增加到15%,光学禁带宽度(Eg)从4.02 eV降低到3.82 eV,Eg的降低主要与BCN薄膜中碳含量的增加有关。     

离子束增强沉积制备碳化硼及C—B—Ti化合物薄膜的结构与力学性能…

利用离子束共混制备具有高硬度、高熔点及良好化学稳定性的Ｃ，Ｂ化合物对于彩和离子束增强沉积技术进行材料表面改性有重要意义。利用对烧结碳化硼合物靶进行溅射沉积，同时利用不同能量的Ａｒ＾＋进行轰击的方法，制备了碳化硼及碳、硼、钛混合膜膜，并对它们的结构与力学性能进行了研究。     

射频磁控溅射制备硼碳氮薄膜

采用射频磁控溅射技术,用六角氮化硼和石墨为溅射靶,以氩气(Ar)和氮气(N2)为工作气体,在Si (100)衬底上制备出硼碳氮薄膜.通过X射线衍射(XRD)、傅里叶红外吸收光谱(FTIR)和X射线光电子能谱(XPS)等分析手段对样品结构、组分进行了分析.结果表明,样品的组成原子之间实现了原子级化合,且薄膜为乱层石墨结构.样品中B、C、N的原子比近似为1:1:1.     

合金元素(Ti,Cr,Ni)对IBAD制备的碳膜性质的影响

本文采用离子束辅助沉积技术（IBAD）制备一系列碳膜，重点分析添加合金元素（Ti，Cr，Ni）对薄膜性质的影响。实验结果表明：添加Ti，Cr，Ni元素对碳膜厚度，硬度无明显影响，但提高了薄膜的结合强度，其中加入Ni后，薄膜的结合强度最好；添加合金元素可以显著减小碳膜的摩擦系数；添加Ti元素碳膜的组织以非晶态为主，与纯碳膜相当。相对于类金刚石薄膜，本实验制备的碳膜试样更接近于类石墨膜。     

脉冲偏压电弧离子镀制备C_(1-x-y)N_xZr_y超硬复合薄膜

用脉冲偏压电弧离子镀方法在保持石墨靶弧流恒定的条件下,通过同步改变锆靶弧流与氮流量,在硬质合金基体上制备了一系列不同成分的C1-x-yNxZry复合薄膜.随着锆靶弧流与N流量增加,薄膜中Zr与N含量都呈线性增加,同时C含量快速减少.Raman光谱显示所制备的薄膜具有DLC特征,而XRD结果显示薄膜中还存在有明显的ZrN晶体相,说明本实验所制备的薄膜属于在DLC非晶基体上匹配有ZrN晶体相的碳基复合薄膜.随Zr与N含量增加,薄膜硬度先增大后降低,当x=0.19,y=0.28时薄膜具有最高硬度值,为43.6GPa,达到了超硬薄膜的硬度值.     

氢化锂薄膜的应用研究

阐述了氢化锂薄膜在惯性约束聚变中的应用背景,介绍了多层膜间隔层和惯性约束聚变中靶丸燃料的研究现状及存在的问题,展望了利用脉冲激光沉积技术制备氢化锂薄膜用作多层膜间隔层和靶丸燃料的发展方向。     

Silicon nitride films synthesized by reactive pulsed laser deposition in an electron cyclotron resonance nitrogen plasma

We report a film synthesis method called electron cyclotron resonance (ECR) plasma aided reactive pulsed laser deposition. Silicon nitride films were synthesized at low temperature by means of laser ablation of a silicon target in an ECR microwave discharge in pure nitrogen gas. It is found that silicon and nitrogen are well-distributed in the deposited films with a composition of near stoichiometric Si₃N₄. Optical emission spectroscopy indicated that nitrogen in the ECR plasma was highly activated. The presence of the ECR nitrogen plasma during the deposition is considered to lead to enhanced nitridation of the ablated silicon in the plume as well as at the substrate, and to be responsible for the effective incorporation of nitrogen in the films.     

Polymer–inorganic nano-composite thin film upconversion light emitters prepared by double-beam matrix assisted pulsed laser evaporation (DB-MAPLE) method

The work was to investigate the possibility of making polymer–inorganic nano-composite films with upconversion fluorescence properties using the double beam matrix-assisted pulsed laser evaporation (DB-MAPLE) method. The existing pulsed laser deposition vacuum chamber was modified to accommodate two laser beams of different wavelengths for simultaneous ablation of two separate targets: a polymer host and a rare earth containing rare earth ion enriched upconversion fluoride dopant. The polymer target was prepared in chlorobenzene and kept frozen during the ablation with circulating liquid nitrogen in accordance with the MAPLE procedure. It was ablated with 1064 nm beam from a pulsed Nd:YAG laser. The pellets made of the synthesized powders of inorganic phosphors of NaYF₄:Yb³⁺, Er³⁺ and NaYF₄:Yb³⁺, Ho³⁺were ablated with 532-nm beam from the same laser. The plumes from both targets were kept overlapping on the substrate during the deposition. X-ray diffraction analysis revealed that the most favorable for upconversion emission of the inorganic target materials was the hexagonal, beta phase of the NaYF₄ matrix existing at a baking temperature between 400 and 600 °C. The fabricated nano-composite films were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and optical fluorescence spectroscopy. The polymer nano-composite films generally retained the crystalline structure and the upconversion fluorescence properties of the initial rare earth compounds due to better control of the deposition process of the materials with substantially different properties. The proposed method can be potentially used for making a wide variety of nano-composite films.     

Effect of deposition temperature on chemical composition and electronic properties of amorphous carbon nitride (a-CNx) thin films grown by plasma assisted pulsed laser deposition

The effect of deposition temperature and nitrogen inclusion in amorphous carbon (a-C) films, deposited by plasma enhanced pulsed laser deposition, on chemical composition and electronic transport has been studied. a-CNx films were deposited on Si (100) by pulsed ArF laser ablation of a graphite target, under N₂ atmosphere. A radiofrequency (13.56 MHz RF) apparatus was used to generate plasma of excited nitrogen species, and its effect on nitrogen uptake and CNx film formation has been studied. Chemical and micro-structural changes associated to increased deposition temperature and nitrogen incorporation were examined by x-ray photoelectron spectroscopy; electrical properties were analyzed by the four-point-probe methods. Temperature-dependent conductivity measurements are tentatively interpreted and discussed in reference to chemical composition.     

Shadowed Off-Axis Pulsed Laser Deposition of YBa2Cu3O7?x Thin Films

Using a shadowed pulsed laser deposition allows us to reduce the number of droplets on the YBa₂Cu₃O_7–x film surface obtained by pulsed laser deposition method. In this study, we present a new modification of pulsed laser deposition method: a shadowed off-axis pulsed laser deposition. The substrate surface lies in the plain defined by the laser beam. A rectangular shadow mask located between target and substrate reduce the quantity of large particles deposited from the diffusion flow. Such geometry allows us to carry out the laser plume scanning on the target surface for simultaneous one-step double-sided deposition films with a droplet-free surface. Both films had good superconducting properties.     

Mechanical properties and bonding structure of boron carbon nitride films synthesized by dual ion beam sputtering

The BCN films were synthesized on Si (110) wafers by using dual ion beam sputtering deposition from boron carbide target. The influences of ion assist source energy and N₂ relative flow rate on the surface roughness, mechanical properties and chemical bonding structure of BCN films were investigated systematically. The surface roughness was measured using non-contact optical surface profilometer and the mechanical properties of BCN films were evaluated with nano-indenter. The BCN films were characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. The results showed that the BCN films' surface roughness varied in the range of 5–15 nm, and their hardness and reduced elastic modulus fluctuated in the scope of 18–29 GPa and 192–229 GPa, respectively. When the BCN films' surface roughness varied in the range of 8–12 nm, the values of hardness and reduced elastic modulus were fluctuated slightly. The BCN films with the smoothest surface (R_a = 5 nm) and the highest hardness of 28 GPa were obtained at the ion assist source energy of 200 eV and the N₂ relative flow rate of 50%. The BCN films were amorphous and contained several bonding states such as B–N, B–C and C–N with B–C–N hybridization.     

电弧离子镀制备CrN_x薄膜中熔滴的结构表征与形成机制

应用电弧离子镀技术,在不同的氮气分压(0.5~2.5 Pa)和脉冲偏压(0~-300 V)条件下对TC4基体沉积CrNx薄膜,采用扫描电镜和透射电镜对镀膜过程中产生的熔滴现象进行分析研究。结果表明,升高氮气分压能减少靶材排出粒子团数量,改变等离子体轰击作用,从而控制熔滴数量及尺寸,改善薄膜表面平整度;脉冲偏压能够使熔滴与薄膜紧密结合,改变熔滴成分,在一定范围内能促进靶材成分熔滴的形成。     

Laser physico-chemical vapour deposition of cubic boron nitride thin films

A laser physico-chemical vapour deposition (LPCVD) technique was developed based on the interaction of an ultraviolet laser beam with a boron nitride target and borazine gas to synthesize cubic boron nitride (CBN) thin films on silicon substrates. The process involved a hybrid of pulsed laser ablation (PLA) of a solid HBN target and chemical vapour deposition (CVD) using borazine as a feed stock. The films were characterized with scanning electron microscopy, X-ray diffraction and infrared spectroscopy. Results indicate that the thin films consisted of almost single-crystalline CBN structures and that the film quality in terms of adherence, particulate density and smoothness was excellent. The purity and crystal structure of target material, laser beam wavelength and energy fluence were the key variables that controlled the film characteristics. In contrast to LPCVD, the conventional PLA method did not generate CBN films.     

Effect of nitrogen environment on NdFeB thin films grown by radio frequency plasma beam assisted pulsed laser deposition

NdFeB is a very attractive material for applications in electrical engineering and in electronics, for high-tech devices where high coercive field and high remanence are needed. In this paper we demonstrate that the deposition of nitrogen doped NdFeB thin films by pulsed laser deposition, in the presence of a nitrogen radiofrequency plasma beam, exhibit improved magnetic properties and surface morphology, when compared to vacuum deposited NdFeB layers. A Nd:YAG pulsed laser (3ω and 4ω) was focused on a NdFeB target, in vacuum, or in the presence of a nitrogen plasma beam. Substrate temperature (RT-850 °C), nitrogen gas pressure, and radiofrequency power (75–150 W), were particularly varied. The thin films were investigated by means of X-ray diffraction, atomic force microscopy, scanning electron microscopy, spectroscopic-ellipsometry, and vibrating sample magnetometry.     

Annealing and recrystallization of amorphous ZnO thin films deposited under cryogenic conditions by pulsed laser deposition

This article deals with the annealing of amorphous ZnO thin films prepared by pulsed laser deposition (PLD) under cryogenic conditions. The substrate holder was cooled by liquid nitrogen. X-ray diffraction analysis evidenced that as-deposited films had amorphous structures: analysis by scanning electron microscopy (SEM) revealed their fine grained surface and inner structure. Annealing at temperatures in the range of 200-800 °C resulted in a transition in the thin film crystal structure from amorphous to polycrystalline. Various properties of the ZnO films were found depending on the recrystallization temperature. In depth investigations employing SEM, X-ray diffraction, atomic force microscopy and secondary ion mass spectroscopy provided comparisons of the recrystallizations of undoped ZnO thin films during the phase transition processes from amorphous to hexagonal wurtzite structures.     

Amorphous carbon nitrogenated films prepared by plasma immersion ion implantation and deposition

In this work, an investigation was conducted on amorphous hydrogenated-nitrogenated carbon films prepared by plasma immersion ion implantation and deposition. Glow discharge was excited by radiofrequency power (13.56 MHz, 40 W) whereas the substrate-holder was biased with 25 kV negative pulses. The films were deposited from benzene, nitrogen and argon mixtures. The proportion of nitrogen in the chamber feed (R_N) was varied against that of argon, while keeping the total pressure constant (1.3 Pa). From infrared reflectance-absorbance spectroscopy it was observed that the molecular structure of the benzene is not preserved in the film. Nitrogen was incorporated from the plasma while oxygen arose as a contaminant. X-ray photoelectron spectroscopy revealed that N/C and O/C atomic ratios change slightly with R_N. Water wettability decreased as the proportion of N in the gas phase increased while surface roughness underwent just small changes. Nanoindentation measurements showed that film deposition by means of ion bombardment was beneficial to the mechanical properties of the film-substrate interface. The intensity of the modifications correlates well with the degree of ion bombardment.