The properties of N-doped diamond-like carbon films prepared by helicon wave plasma chemical vapor deposition

In this paper, N-doped diamond-like carbon(DLC) films were deposited on silicon substrates by using helicon wave plasma chemical vapor deposition(HWP-CVD) with the Ar/CH_4/N_2 mixed gas. The surface morphology, structural and mechanical properties of the N-doped DLC films were investigated in detail by scanning electron microscopy(SEM), x-ray photoelectron spectroscopy(XPS), Raman spectra, and atomic force microscopy(AFM). It can be observed from SEM images that surface morphology of the films become compact and uniform due to the incorporation of N. The maximum of the deposition rate of the films is 143 nm min~(-1), which is related to the high plasma density. The results of XPS show that the N incorporates in the films and the C-C sp~3 bond content increases firstly up to the maximum(20%) at 10 sccm of N_2 flow rate, and then decreases with further increase in the N_2 flow rate. The maximum Young's modulus of the films is obtained by the doping of N and reaches 80 GPa at 10 sccm of N_2 flow rate, which is measured by AFM in the scanning probe microscope mode. Meanwhile, friction characteristic of the N-doped DLC films reaches a minimum value of 0.010.     

Surface Modification of Biodegradable Poly(D,L-lactic acid)by Nitrogen and Nitrogen/Hydrogen Plasma for Improving Surface Hydrophilicity

Enhancement of the surface hydrophilicity of biodegradable poly (D,L-lactic acid) (PLA) films is studied. The PLA films were treated by nitrogen plasma (PLA-N2) and nitrogen/hydrogen plasma (PLA-N2/H2), respectively. The surface properties and microstructure of PLA-N2 and PLA-N2/H2 were studied by static contact angle measurement, surface free energy calculation, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). It is confirmed that the surface hydrophilicity of PLA-N2 and PLA-N2/H2 was higher than that of pristine PLA, and the surface hydrophilicity of PLA-N2 films was better than that of PLA-N2/H2.     

原位光电子能谱研究La_2O_3/LaAlO_3/Si电子结构

在超高真空条件下,通过脉冲激光技术沉积La_2O_3/LaAlO_3/Si多层膜结构,原位条件下利用同步辐射光电子能谱研究了LaAlO_3作为势垒层的La_2O_3与Si的界面电子结构。实验结果显示,LaAlO_3中Al的2p峰在沉积和退火前后没有变化;衬底硅的芯能级峰在沉积LaAlO_3时没有变化,但在沉积La_2O_3薄膜和退火过程中,硅峰变弱;O的1S芯能级的峰由多种不用的氧化物薄膜层和反应物中的氧杂化而成。结果表明:LaAlO_3从沉积到退火当中,不参与任何反应,Si与LaAlO_3界面相当稳定;在体系中,阻挡层LaAlO_3起到阻挡硅扩散的作用,进一步表明La_2O_3与硅的界面不太稳定。     

Incorporation of Nitrogen into Amorphous Carbon Films Produced by Surface-Wave Plasma Chemical Vapor Deposition

In order to study the influence of nitrogen incorporated into amorphous carbon films, nitrogenated amorphous carbon films have been deposited by using surface wave plasma chemical vapor deposition under various ratios of N2/CH4 gas flow. Optical emission spectroscopy has been used to monitor plasma features near the deposition zone. After deposition, the samples are checked by Raman spectroscopy and x-ray photo spectroscopy (XPS). Optical emission intensities of CH and N atom in the plasma are found to be enhanced with the increase in the N2/CH4 gas flow ratio, and then reach their maximums when the N2/CH4 gas flow ratio is 5%. A contrary variation is found in Raman spectra of deposited films. The intensity ratio of the D band to the G band (ID/IG) and the peak positions of the G and D bands all reach their minimums when the N2/CH4 gas flow ratio is 5%. These show that the structure of amorphous carbon films has been significantly modified by introduction of nitrogen。     

团簇沉积C-N薄膜的研究

利用荷能团族沉积装置在高阻硅（111）衬底上沉积了碳氮薄膜。通过红外光谱、拉曼谱和X光电子能谱对薄膜的结构和化学组分进行了分析。结果表明,薄膜中存在N－sp^3(β－C3N4的键合方式）,但以N－^2C和C＝C双键的结合方式为主。     

Sheet Resistance and Gas-Sensing Properties of Tin Oxide ThinFilms by Plasma Enhanced Chemical Vapor Deposition＊

Tin oxide (SnO2) thin films are prepared at different temperatures by plasmaenhanced chemical vapor deposition (PECVD). The structural characterizations of the films are investigated by various analysis techniques. X-ray diffraction patterns (XRD) show that the phase of SnO2 films are different at different deposition temperatures. The sheet resistance of the films decreases with increase of deposition temperature. X-ray photoelectron spectroscopy (XPS) shows that the SnO2 thin film is non-stoichiometric. The sheet resistance increases with increase in oxygen flow. Sb-doped SnO2 thin films are more sensitive to alcohol than carbon monoxide, and its maximum sensitivity is about 220％.     

氢气流量对类金刚石薄膜结构与性能的影响

采用直流/射频耦合反应磁控溅射法在Si（100）衬底上成功制备出类金刚石（DLC）薄膜。利用表面轮廓仪、Raman光谱仪、X射线光电子能谱仪表征所制备薄膜在不同氢气流量下的沉积速率和化学结构,讨论了氢气流量对薄膜沉积速率和化学结构的影响;利用纳米压痕技术及曲率弯曲法表征薄膜的力学性能;利用扫描电镜和原子力显微镜表征薄膜的表面形貌与粗糙度。研究表明：随着氢气流量的增加,所制备薄膜的沉积速率逐渐减小,而薄膜中sp³键的含量逐渐增大。当氢气流量为25 mL/min时,薄膜中sp³键的含量为36.3%,薄膜的硬度和体弹性模量分别达到最大值17.5 GPa和137 GPa。同时,所制备薄膜的内应力均低于0.5 GPa,有望成功制备出低内应力的高质量DLC厚膜。随着氢气流量的增加,DLC薄膜的表面变得更致密光滑,且表面均方根粗糙度由5.40 nm降为1.46 nm。     

The effect of nitrogen concentration on the properties of N-DLC prepared by helicon wave plasma chemical vapor deposition

Nitrogen-doped diamond-like carbon (N-DLC) films were synthesized by helicon wave plasma chemical vapor deposition (HWP-CVD). The mechanism of the plasma influence on the N-DLC structure and properties was revealed by the diagnosis of plasma. The effects of nitrogen doping on the mechanical and hydrophobicity properties of DLC films were studied. The change in the ratio of precursor gas flow reduces the concentration of film-forming groups, resulting in a decrease of growth rate with increasing nitrogen flow rate. The morphology and structure of N-DLC films were characterized by scanning probe microscopy, Raman spectroscopy, and X-ray photoemission spectroscopy. The mechanical properties and wettability of N-DLC were analyzed by an ultra-micro hardness tester and JC2000DM system. The results show that the content ratio of N+ and ${{\rm{N}}}_{2}^{+}$ is positively correlated with the mechanical properties and wettability of N-DLC films. The enhancement hardness and elastic modulus of N-DLC are attributed to the increase in sp3 carbon–nitrogen bond content in the film, reaching 26.5 GPa and 160 GPa respectively. Water contact measurement shows that the increase in the nitrogen-bond structure in N-DLC gives the film excellent hydrophobic properties, and the optimal water contact angle reaches 111.2°. It is shown that HWP technology has unique advantages in the modulation of functional nanomaterials.     

Influence of Different CH4/N2 Ratios on Structural and Mechanical Properties of a-CNx:H Film Synthesized Using Plasma Focus

Carbon nitride films were synthesized by operating the dense plasma focus device with different CH₄/N₂ admixture gas ratios and fixed 20 focus shots. The pressure and axial distance from anode tip were kept constant at 3 mbar and 8 cm respectively. Raman and X-ray photoelectron spectroscopy (XPS) techniques were used to observe the effect of CH₄/N₂ ratio on carbon nitride bonding. The XPS analysis showed that the terminating group C≡N is more dominant for the films synthesized using higher concentration of nitrogen which gives softer films. Field emission scanning electron microscopy results showed that the deposited films consist of nanoparticles and their agglomerates. The size of agglomerates increases with decreasing concentration of nitrogen in CH₄/N₂ admixture gas. Nanoindentation results showed the increase in hardness and elastic modulus values of films with decreasing concentration of nitrogen in CH₄/N₂ admixture gas. The hardness and elastic modulus values were found to be dependent on sp³ content in the film as well as the C≡N. The hardness and elastic modulus values of 10.7 and 229.8 GPa respectively were achieved for the films deposited with fixed 20 focus deposition shots and using CH₄/N₂ admixture gas ratio of 7:3.     

硼缓冲注入层对氮化硼薄膜生长的影响

采用射频磁控溅射法在注硼的硅和高速钢基体上沉积制备c-BN薄膜,采用红外光谱(Infrared spectra,IR)、X射线光电子能谱(X-ray photoelectron spectrum,XPS)和原子力显微镜(Atomicforce microscopy, AFM)等分析方法对沉积的薄膜进行了表征分析.实验结果表明:硅基体上离子注硼有利于c-BN薄膜内应力的降低;合适的注硼量注入高速钢基体有利于c-BN的生成和薄膜内应力的降低.AFM分析表明,注硼处理的高速钢基体上沉积的薄膜表面形貌平整,结晶性较好.此外也采用XPS方法对硅和高速钢基体硼过渡层进行了成分与组织结构分析,探索研究了硼缓冲层对c-BN薄膜生长的影响.     

基于单一气源的PECVD方法制备SiC薄膜及其微观结构研究

为制备出满足惯性约束聚变（ICF）实验要求的SiC薄膜,本文采用等离子体增强化学气相沉积（PECVD）法,以四甲基硅（TMS）作为唯一反应气源,在不同工作压强下制备SiC薄膜。利用扫描电子显微镜、表面轮廓仪、原子力显微镜、精密电子天平、X射线光电子能谱、傅里叶变换红外光谱对薄膜进行表征与分析。结果表明：SiC薄膜的成分与工作压强密切相关,随着工作压强的增加,薄膜中Si含量整体呈下降趋势;随着工作压强的增加,薄膜沉积速率先增大后减少,密度先减小后增大;与其他制备工艺相比,采用单一气源制备SiC薄膜,其表面粗糙度极低（1.25～1.85 nm）,薄膜粗糙度随工作压强的增加呈先增大后减小的趋势。     

Study on deposition of Al2O3 films by plasma-assisted atomic layer with different plasma sources

In this paper,A12O3 thin films are deposited on a hydrogen-terminated Si substrate by using two home-built electron cyclotron resonance (ECR) and magnetic field enhanced radio frequency plasma-assisted atomic layer deposition (PA-ALD) devices with Al(CH3)3 (trimethylaluminum,TMA) and oxygen plasma used as precursor and oxidant,respectively.The thickness,chemical composition,surface morphology and group reactions are characterized by in situ spectroscopic ellipsometer,x-ray photoelectric spectroscopy,atomic force microscopy,scanning electron microscopy,a high-resolution transmission electron microscope and in situ mass spectrometry (MS),respectively.We obtain that both ECR PA-ALD and the magnetic field enhanced PA-ALD can deposit thin films with high density,high purity,and uniformity at a high deposition rate.MS analysis reveals that the A12O3 deposition reactions are not simple reactions between TMA and oxygen plasma to produce alumina,water and carbon dioxide.In fact,acetylene,carbon monoxide and some other by-products also appear in the exhaustion gas.In addition,the presence of bias voltage has a certain effect on the deposition rate and surface morphology of films,which may be attributed to the presence of bias voltage controlling the plasma energy and density.We conclude that both plasma sources have a different deposition mechanism,which is much more complicated than expected.     

Erosion of thin hydrogenated carbon films in oxygen,oxygen/hydrogen and water plasmas

The erosion of amorphous hydrogenated carbon films in oxygen, oxygen/hydrogen and water electron cyclotron resonance plasmas was investigated by in situ ellipsometry. The erosion was measured as a function of the energy of the impinging ions and the substrate temperature. Erosion is most effective in pure oxygen plasmas. The erosion rate rises with increasing ion energy and substrate temperature, in the latter case however only at low ion energies. The reaction layer at the surface of the eroded film is further analyzed by X-ray photoelectron spectroscopy (XPS). The C 1s peak of the XPS spectra shows, that oxygen is implanted in the films and forms double and single bonds to the carbon atoms. This modification, however, is limited to a few atomic layers.     

Atomic layer deposition of copper thin film and feasibility of deposition on inner walls of waveguides

Copper thin films were deposited by plasma-enhanced atomic layer deposition at low temperature, using copper(I)-N,N′-di-sec-butylacetamidinate as a precursor and hydrogen as a reductive gas. The influence of temperature, plasma power, mode of plasma, and pulse time, on the deposition rate of copper thin film, the purity of the film and the step coverage were studied.The feasibility of copper film deposition on the inner wall of a carbon fibre reinforced plastic waveguide with high aspect ratio was also studied. The morphology and composition of the thin film were studied by atomic force microscopy and x-ray photoelectron spectroscopy,respectively. The square resistance of the thin film was also tested by a four-probe technique. On the basis of on-line diagnosis, a growth mechanism of copper thin film was put forward, and it was considered that surface functional group played an important role in the process of nucleation and in determining the properties of thin films. A high density of plasma and high free-radical content were helpful for the deposition of copper thin films.     

动态离子束混合技术制备氧化铬薄膜的X射线光电子能谱与俄歇电子能谱研究

本文介绍的动态离子束混合技术制备氧化铬薄膜系在不锈钢基体上进行1keV氩离子束溅射沉积铬(同时通入一定量的O),并用100 keV的氩离子束或氧离子束轰击该样品.对两种离子束轰击形成的氧化铬薄膜进行了X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和俄歇电子能谱(Auger electron spectroscopy,AES)的分析研究.发现Ar 离子束制备的氧化铬薄膜主要是Cr2O3化合物,而O 离子束制备的氧化铬薄膜含有其它价态的铬氧化物.Ar 离子束制备氧化铬薄膜的污染碳少于O 离子束制备.与O 离子束制备相比较,相同能量的Ar 离子束轰击更有利于提高沉积的Cr原子与周围O2的反应性;Ar 离子束制备的氧化铬薄膜过渡层的厚1/3左右,较厚的过渡层显示了制备的薄膜具有较好的附着力.     

Fabrication of Si–C–N compounds in silicon carbide by ion implantation

The chemical variation and depth profile of silicon carbide implanted with nitrogen and overgrown with epitaxial layer has been studied using X-ray photoelectron spectroscopy (XPS). The results of this study have been supplemented by transmission electron microscopy (TEM) imaging and electron energy loss-spectroscopy (EELS) in an attempt to correlate the chemical and structural information. Our results indicate that the nitrogen implantation into silicon carbide results in the formation of the Si–C–N layer. XPS revealed significant change in the bonding structure and chemical states in the implanted region. XPS results can be interpreted in terms of the silicon nitride and silicon carbonitride nanocrystals formation in the implanted region which is supported by the electron microscopy and spectroscopy results.     

Reactive DC Magnetron Sputter Deposited Titanium-Copper-Nitrogen Nano-Composite Thin Films with an Argon/Nitrogen Gas Mixture

A sintered Ti13Cu87 target was sputtered by reactive direct current (DC) magnetron sputtering with a gas mixture of argon/nitrogen for different sputtering powers. Titanium-copper-nitrogen thin films were deposited on Si (111), glass slide and potassium bromide (KBr) substrates. Phase analysis and structural properties of titanium-copper-nitrogen thin films were studied by X-ray diffraction (XRD). The chemical bonding was characterized by Fourier transform infrared (FTIR) spectroscopy. The results from XRD show that the observed phases are nano-crystallite cubic anti rhenium oxide (anti ReO3) structures of titanium doped Cu3N (Ti:Cu3N) and nano-crystallite face centered cubic (fcc) structures of copper. Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDX) were used to determine the film morphology and atomic titanium/copper ratio, respectively. The films possess continuous and agglomerated structure with an atomic titanium/copper ratio ( 0.07) below that of the original target ( 0.15). The transmittance spectra of the composite films were measured in the range of 360 to 1100 nm. Film thickness, refractive index and extinction coefficient were extracted from the measured transmittance using a reverse engineering method. In the visible range, the higher absorption coefficient of the films prepared at lower sputtering power indicates more nitrification in comparison to those prepared at higher sputtering power. This is consistent with the formation of larger Ti:Cu3N crystallites at lower sputtering power. The deposition rate vs. sputtering power shows an abrupt transition from metallic mode to poisoned mode. A complicated behavior of the films’ resistivity upon sputtering power is shown.     

CHN薄膜的制备

文章简要描述了空心阴极等离子体化学气相沉积(HPCVD)的原理，以及用HPCVD方法制备CHN薄膜的工艺和实验结果。用XPS和AFM分别分析了CHN薄膜中C和N的成分及表面形貌，并得到了一定条件下的薄膜沉积速率。     

Synthesis of carbon-nitride films using a fast-switched dual-source low energy ion beam deposition system

Thin C_xN_y films were deposited in UHV using alternating low energy ion beams of C⁺ and N⁺ or N₂⁺ in the energy range of 5 to 100 eV. The ion beam deposition system is equipped with two Freeman ion sources, mass analysis and fast automated beam switching, allowing perpendicular bombardment of the target with a single ion beam at a time. The composition and density of the films were studied by ARS (in situ), XPS and RBS. The dependence of the film properties and growth mechanisms on ion energy, beam switching rate, and C-to-N arrival ratio have been investigated. The influence of the deposition parameters on the film stoichiometry is discussed. Exposure of the film to atmosphere leads to oxygen incorporation, resulting in a lowered surface concentration of nitrogen. The XPS N 1s and C Is binding energies vary in a relatively broad range indicating that several bond states may be present. The influence of the substrate material on film growth has also been studied. On Si{100}, film growth commences with the formation of an interfacial silicon nitride. No film growth was observed on gold, however deposition was possible on tantalum and molybdenum.