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。     

工作压强对SiC空心微球结构及性能的影响

采用化学气相沉积（CVD）-高温热解法,在不同工作压强条件下,制备了惯性约束聚变靶用SiC空心微球。利用X射线光电子能谱仪、扫描电子显微镜、白光干涉仪、X射线照相机对SiC空心微球的成分、表面形貌、表面粗糙度、球形度以及壁厚均匀性进行了测试与分析。研究结果表明：随工作压强的增加,SiC空心微球的表面均方根粗糙度先减小后增加,当工作压强为15 Pa时,表面均方根粗糙度达到最小值98 nm;随工作压强的增加,SiC空心微球的球形度未发生明显变化,且均优于97%;而壁厚均匀性则随工作压强的增加先增加后减小,当压强为15 Pa时,壁厚均匀性可达95%。     

反式二丁烯与氢气流量比对辉光放电等离子体组分与聚合物薄膜表面粗糙度的影响

采用低压等离子体增强化学气相沉积方法（LPPE-CVD）,以反式二丁烯（T₂B）和氢气（H₂）为工作气体,改变T₂B/H₂流量比制备不同条件下的碳氢聚合物（GDP）薄膜。利用质谱诊断技术研究了工作气体流量比对薄膜沉积过程中等离子体组分及离化程度的影响规律。同时结合白光干涉和SEM等技术研究了GDP薄膜的表面粗糙度和表面形貌的变化规律。结果表明,随T₂B/H₂流量比的增加,反应腔室中等离子体的离化率呈现先增大后减小的趋势。当T₂B/H₂流量比为0.8∶10时,反应气体的裂解程度最大,等离子体中离子片段的总量也最多。薄膜的表面粗糙度随T₂B/H₂流量比的增加出现先减小后增大的趋势。在0.6∶10的T₂B/H₂流量比条件下,薄膜的均方根粗糙度R_q达到极小值39.1 nm。     

高质量类金刚石薄膜的制备与性能分析

采用直流/射频耦合磁控溅射法在Si(100)衬底上成功制备出类金刚石(DLC)薄膜。利用Raman光谱仪、X射线光电子能谱仪表征不同射频功率下所制备薄膜的化学结构,讨论射频功率对薄膜化学结构的影响。采用X射线小角反射法表征薄膜的质量密度,利用曲率弯曲法表征薄膜的残余内应力,采用扫描电镜和原子力显微镜表征所制备薄膜的表面形貌与粗糙度。研究表明:薄膜中sp3键的含量随着射频功率的增加而呈现出先增大后减小的趋势,且在射频功率为40 W时达到最大值45.6%。随着射频功率的增加,薄膜的表面粗糙度呈现出先减小后增大的趋势,当射频功率为40 W时薄膜的表面粗糙度最小,为1.6 nm。直流/射频耦合磁控溅射法在不同射频功率下制备出的薄膜,其内应力均低于1.0 GPa,薄膜质量密度的变化范围为2.26~2.44 g/cm~3,有望成功制备出内应力低、密度高的高质量DLC薄膜。     

基于动力学标度法的a-C:H薄膜表面微观形貌的演变机理研究

采用等离子体增强化学气相沉积(PECVD)方法在Si(111)基底上制备a-C:H薄膜,利用原子力显微镜(AFM)和扫描电子显微镜(SEM)对a-C:H薄膜的表面形貌与表面粗糙度进行表征,并从动力学标度法角度出发讨论a-C:H薄膜表面粗糙度的演变机理。研究结果表明:a-C:H薄膜表面微观形貌为自仿射分形表面,可用分形维数来评价薄膜的表面粗糙度;随着H_2流量的增加,薄膜表面粗糙度先减小后增大,在T_2B与H_2流量比为0.2/6时,a-C:H薄膜的表面粗糙度R_q为2.2nm,相对于其他条件下生长的薄膜的表面粗糙度低,薄膜表面较光滑,致密性良好。     

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。     

α-C_xN_y:H_(1-x-y)薄膜的制备和光学性能分析

采用外置式电容耦合低压等离子体化学气相沉积法,以高纯CH4/N2/H2作为反应气体,制备非晶α-CxNy:H1-x-y薄膜。研究了薄膜沉积速率和入射功率之间的关系,随着功率增大,薄膜沉积速率先增大后减小;SEM图像表明薄膜无层状、柱状结构;AFM图像表明薄膜粗糙度在0.2～0.3nm之间;傅里叶红外光谱(FTIR)显示了薄膜的成键情况;紫外-可见-近红外光谱表明,随着入射功率的增大,薄膜的光学带隙逐渐减小。     

超高真空脉冲激光沉积Au、U单层膜及Au/U/Au复合膜研究

采用超高真空脉冲激光沉积（PLD）方法,在单晶Si基底表面制备了单层Au、单层U薄膜和Au/U/Au复合薄膜,应用SEM、白光干涉轮廓分析和AES分析,研究了靶基距、基片温度和激光能量对薄膜形貌、成分的影响。目前的实验结果显示,PLD所制备的Au、U薄膜表面有μm级以下粒径的液滴产生,在液滴较少位置,薄膜表面粗糙度R_a小于1 nm,在包含大液滴位置,R_a不超过15 nm。在相同沉积条件下,U薄膜表面液滴数量大于Au薄膜。优化单层薄膜沉积工艺后制备的Au/U/Au复合膜厚度约为195 nm,均方根粗糙度R_q在0.3～1.5 nm之间。AES分析显示,Au/U/Au复合膜中强化学活性的铀呈金属状态,复合膜中的氧含量低于5%（原子百分数）,表层Au薄膜对U薄膜起到了良好的防氧化作用。在沉积工艺中,通过减小激光功率、增大靶基距并适当升高基片温度,可减少液滴的数量及粒径。     

磁控溅射法制备金/钆柱腔工艺研究

采用直流磁控溅射方法制备金/钆(Au/Gd)多层膜,并研究不同制备参数对多层膜结构与性能的影响。溅射压强高于1Pa时,Au膜与Gd膜的沉积速率均随溅射压强的增大而下降;在较低溅射气压下,随着溅射气压的降低,金膜与钆膜的均方根粗糙度有所减小;随着溅射功率的减小,金/钆多层膜的周期性结构变好,界面更为清晰。本工作制备了不同原子比的金/钆膜柱腔,探讨了有关柱腔成型的解决方法。     

磁控溅射制备金属铀膜

研究了通过磁控溅射方法制备高纯金属铀膜的可行性。采用X射线衍射（XRD）、俄歇电子能谱（AES）、扫描电镜（SEM）、表面轮廓仪分析了沉积在单晶硅或金基材上铀薄膜的微观结构、成分、界面结构及厚度、表面形貌和表面粗糙度。分析结果表明：磁控溅射制备的铀薄膜为纯金属态,氧含量和其它杂质含量均低于俄歇电子能谱仪的探测下限;溅射沉积的铀镀层与铝镀层之间存在界面作用,两者相互扩散并形成合金相,扩散层厚度约为10nm。铀薄膜厚度可达微米级,表面光洁,均方根（RMS）粗糙度优于15nm。     

Investigation of working pressure on the surface roughness controlling technology of glow discharge polymer films based on the diagnosed plasma

The effects of working pressure on the component, surface morphology, surface roughness, and deposition rate of glow discharge polymer(GDP) films by a trans-2-butene/hydrogen gas mixture were investigated based on plasma characteristics diagnosis. The composition and ion energy distributions of a multi-carbon(C_4H_8/H_2) plasma mixture at different working pressures were diagnosed by an energy-resolved mass spectrometer(MS) during the GDP film deposition process. The Fourier transform infrared spectroscopy(FT–IR), field emission scanning electron microscope(SEM) and white-light interferometer(WLI) results were obtained to investigate the structure, morphology and roughness characterization of the deposited films, respectively. It was found that the degree of ionization of the C_4H_8/H_2 plasma reduces with an increase in the working pressure. At a low working pressure, the C–H fragments exhibited small-mass and high ion energy in plasma. In this case, the film had a low CH_3/CH_2 ratio, and displayed a smooth surface without any holes, cracks or asperities. While the working pressure increased to 15 Pa,the largest number of large-mass fragments led to the deposition rate reaching a maximum of 2.11 μm h~(-1), and to hole defects on the film surface. However, continuing to increase the working pressure, the film surface became smooth again, and the interface between clusters became inconspicuous without etching pits.     

Optical Characterization of Diamond Synthesis Using CH3OH-H2 Gas Mixtures

Diamond films with high infrared transmittance have been successfully deposited using CH3OH-H2 gas mixtures through microwave plasma enhanced chemical vapor deposition (MWCVD). The primary purpose of this study is to determine the effect of the deposition conditions on the optical properties of MWCVD diamond films using CH3OH-H2 gas mixtures. Room temperature optical properties of freestanding diamond films were studied by Fourier transform IR spectroscopy. Experimental results indicated that under appropriate deposition temperature (620 ℃) and methanol concentration (5.7%), the refractive index of CVD diamond films (2.33) was comparable with that of natural diamond (2.417). The average infrared transmittance was above 65% in the middle infrared region (500 cm^-1 - 4000 cm^-1), approaching to the theoretical value of diamond (71.4%). The mechanism of growing high IR transmittance diamond films by utilizing CH3OH-H2 gas system is that the high methanol concentration used in this study makes the surface roughness of diamond films decreased by increasing the secondary nucleation density and the high O/C ratio in CH3OH-H2 gas system, improved the quality of diamond films and therefore decreased the absorption of non-diamond carbon in the films.     

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％.     

Super-hydrophobic film deposition by an atmospheric-pressure plasma process and its anti-icing characteristics

In this work, the super-hydrophobic (SH) surface was prepared through chemical vapor deposition process by an argon atmospheric pressure plasma jet source with HMDSN (hexamethyldisilazane) as the polymerization precursor. Plasma synthesized organosilicon (SiO_xC_yH_z) thin films with water contact angle over 160° and sliding angle below 5°, were able to be achieved. FTIR and XPS analysis indicates a large number of hydrocarbon compositions were polymerized in the thin films enduing the latter very-low surface free energy. SEM shows the SH films display micro-nanostructure and with high degree of averaged surface roughness 190 nm evaluated by AFM analysis. From experiments under controlled low-temperature and moisture conditions, the prepared SH surface exhibits good anti-icing effects. Significantly prolonging freezing time was achievable on the SH thin films for both static and sliding water droplets. This investigation demonstrates the anti-icing potentials of SH surface prepared through low-cost simple atmospheric-pressure plasma polymerization process.     

Plasma Modified Polypropylene Membranes as the Lithium-Ion Battery Separators

To reduce the thermal shrinkage of the polymeric separators and improve the safety of the Li-ion batteries,plasma treatment and plasma enhanced vapor chemical deposition（PECVD）of SiO_x-like are carried out on polypropylene（PP）separators,respectively.Critical parameters for separator properties,such as the thermal shrinkage rate,porosity,wettability,and mechanical strength,are evaluated on the plasma treated PP membranes.O₂ plasma treatment is found to remarkably improve the wettability,porosity and electrolyte uptake.PECVD SiO_x-like coatings are found to be able to effectively reduce the thermal shrinkage rate of the membranes and increase the ionic conductivity.The electrolyte-philicity of the Si Ox-like coating surface can be tuned by the varying O₂ content in the gas mixture during the deposition.Though still acceptable,the mechanical strength is reduced after PECVD,which is due to the plasma etching.     

Physical Properties of Silver Oxide Thin Film Prepared by DC Magnetron Sputtering: Effect of Oxygen Partial Pressure During Growth

In this paper the physical properties of silver oxide thin film have been prepared on BK7 substrate at room temperature by reactive DC magnetron sputtering technique using pure silver metal target by varying oxygen partial pressure during growth at reported. The reactive sputter gas was a mixture of Ar (99.999%) and N₂ (99.999%) with the different ratio Ar and N₂ by volume at the constant pressure of the growth chamber. The X-ray diffraction measurements showed that by increasing O₂ volume during the Growth, change in crystalline structure will occur. The Atomic Force Microscope images shown by increasing O₂ volume, the RMS roughness decreasing consistently. The thickness of the thin films decreases (from 353 to 230 nm) with increasing oxygen partial pressure in chamber. The reflectivity of thin films was investigated with a spectrophotometer system, and the surface reflectivity measurements indicate that by increasing O₂ volume growth, the optical properties of the films changes.     

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.     

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.