Microstructure and Mechanical Properties of CrN Films Deposited by Inductively Coupled Plasma Enhanced Radio Frequency Magnetron Sputtering

CrN films have been synthesized on Si（100） wafer by inductively coupled plasma （ICP）-enhanced radio frequency （RF） magnetron sputtering. The effects of ICP power on microstructure, crystal orientation, nanohardness and stress of the CrN films have been investigated. With the increase of ICP power, the current density at substrate increases and the films exhibit denser structure, while the DC self-bias of target and the deposition rate of films decrease. The films change from crystal structure to amorphous structure with the increase of ICP power. The measured nanohardness and the compressive stress of films reach the topmost at ICP power of 150 W and 200 W, respectively. The mechanical properties of films show strong dependence on the crystalline structure and the density influenced by the ICP power.     

Cleaning of HT-7 Tokamak Exposed First Mirrors by Radio Frequency Magnetron Sputtering Plasma

The stainless steel （SS） first mirror pre-exposed in the deposition-dominated envi- ronment of the HT-7 tokamak was cleaned in the newly built radio frequency （RF） magnetron sputtering plasma device. The deposition layer on the FM surface formed during the exposure was successfully removed by argon plasma with a RF power of about 80 W and a gas pressure of 0.087 Pa for 30 min. The total reflectivity of the mirrors was recovered up to 90% in the wavelength range of 300-800 nm, while the diffuse reflectivity showed a little increase, which was attributed to the increase of surface roughness in sputtering, and residual contaminants. The FMs made from single crystal materials could help to achieve a desired recovery of specular reflectivity in the future.     

Plasma Uniformity in a Dual Frequency Capacitively Coupled Plasma Reactor Measured by Optical Emission Spectroscopy

Local measurement of plasma radial uniformity was performed in a dual frequency capacitively coupled argon plasma (DF-CCP) reactor using an optical probe. The optical probe collects the light emission from a small separate volume in plasma, thus enabling to diagnose the plasma uniformity for different experimental parameters. Both the gas pressure and the low-frequency (LF) power have apparent effects on the radial uniformity of argon plasma. With the increase in either pressure or LF power, the emission profiles changed from a bell-shaped to a double-peak distribution. The influence of a fused-silica ring around the electrodes on the plasma uniformity was also studied using the optical probe. Possible reasons that result in nonuniform plasmas in our experiments are discussed.     

Iterative Calculation of Plasma Density from a Cylindrical Probe Characteristic

A novel method is proposed for treating cylindrical probe characteristics to obtain plasma density. The method consists of exponential extrapolation of the transitional part of the I -V curve to the floating potential for the ion saturation current, other than the existing theories which use the ion branch, and an iterative sheath thickness correction procedure for improved accuracy. The method was tested by treating Langmuir probe I-V characteristics obtained from inductively coupled Ar discharges at various pressures, and comparing the present results with those deduced by existing theories. It was shown that the plasma densities obtained by the present method are in good agreement with those calculated by the Allen-Boyd-Reynolds (ABR) theory, suggesting the effectiveness of the proposed method. Without need of manual setting and adjustment of fitting parameters, the method may be suitable for automatic and real time processing of probe characteristics.     

Cu Films Deposited by Unbalanced Magnetron Sputtering Enhanced by ICP and External Magnetic Field Confinement

Metallic copper（Cu） films were deposited on a Si （100） substrate by unbalanced magnetron sputtering enhanced by radio-frequency plasma and external magnetic field confinement. The morphology and structure of the films were examined by scanning electron microscopy （SEM）, atomic force microscope （AFM） and X-ray diffraction （XRD）. The surface average roughness of the deposited Cu films was characterized by AFM data and resistivity was measured by a four-point probe. The results show that the Cu films deposited with radio-frequency discharge enhanced ionization and external magnetic field confinement have a smooth surface, low surface roughness and low resistivity. The reasons may be that the radio-frequency discharge and external magnetic field enhance the plasma density, which further improves the ion bombardment effect under the same bias voltage conditions. Ion bombardment can obviously influence the growth features and characteristics of the deposited Cu films.     

Experimental Investigation of Surface Wave Plasma Excited by a Cylindrical Dielectric Rod

An improved surface wave plasma source equipped with a cylindrical quartz rod has been developed, which has great potential in processing inner wall of cylindrical workpieces. A cylindrical quartz rod not only excites the plasma around the rod, but also guides surface wave plasma along the rod. The distributions of plasma density and plasma temperature under different incident microwave powers and pressures are diagnosed by a Langmuir probe. The electron density near the rod is around the order of 10^11cm^-3. When the incident power is 450 W, the length of surface wave plasma column can reach up to 420 mm at 20 Pa.     

Radio Frequency Induction Plasma Spraying of Molybdenum

Radio frequency (RF) induction plasma was used to make free-standing deposition of molybdenum (Mo). The phenomena of particle melting, flattening, and stacking were investigated. The effect of process parameters such as plasma power, chamber pressure, and spray distance on the phenomena mentioned above was studied. Scanning electron microscopy (SEM) was used to analyze the plasma-processed powder, splats formed, and deposits obtained. Experimental results show that less Mo particles are spheroidized when compared to the number of spheroidized tungsten (W) particles at the same powder feed rate under the same plasma spray condition. Molten Mo particles can be suf[iciently flattened on substrate. The influence of the process parameters on the flattening behavior is not significant. Mo deposit is not as dense as W deposit, due to the splash and low impact of molten Mo particles. Oxidation of the Mo powder with a large particle size is not evident under the low pressure plasma spray.     

Diagnosis of Unmagnetized Plasma Electron Number Density and Electron-neutral Collision Frequency by Using Microwave

The plasma diagnostic method using the transmission attenuation of microwaves at double frequencies （PDMUTAMDF） indicates that the frequency and the electron-neutral collision frequency of the plasma can be deduced by utilizing the transmission attenuation of microwaves at two neighboring frequencies in a non-magnetized plasma. Then the electron density can be obtained from the plasma frequency. The PDMUTAMDF is a simple method to diagnose the plasma indirectly. In this paper, the interaction of electromagnetic waves and the plasma is analyzed. Then, based on the attenuation and the phase shift of a microwave in the plasma, the principle of the PDMUTAMDF is presented. With the diagnostic method, the spatially mean electron density and electron collision frequency of the plasma can be obtained. This method is suitable for the elementary diagnosis of the atmospheric-pressure plasma.     

溅射功率对磁控溅射制备Bi薄膜结构和性能的影响

采用直流磁控溅射方法在不同功率下制备了铋(Bi)薄膜,对薄膜的沉积速率、表面形貌、生长模式、晶体结构进行了研究,并对其晶粒尺寸和应力的变化规律进行了分析。扫描电镜(SEM)图像显示：薄膜均为柱状生长,平均晶粒尺寸随溅射功率先增大后减小,薄膜的致密度随着功率的增加而降低,在60W时又变得较致密。X射线衍射(XRD)结果表明：Bi薄膜均为多晶斜六方结构,薄膜内应力随功率的增加由张应力变为压应力。     

直流磁控溅射钛及钛合金薄膜的性能研究

用直流磁控溅射的方法在Si及Mo基片上制取Ti及其Ti合金薄膜。研究了基片温度等镀膜工艺参数对薄膜性能的影响,并用XPS、XRD、SEM分析薄膜的化学组成和结构特征,对薄膜的生长模式进行分析。结果表明,合金的加入降低了晶粒尺寸;升高温度可增大薄膜晶粒尺寸,改善薄膜结合能力;合金膜的成分与靶材基本一致。     

Investigation of Microwave Surface-Wave Plasma Deposited SiOxCoatings on Polymeric Substrates简

In this paper, we reported nano-scale SiOx coatings deposited on polyethylene terephthalate （PET） webs by microwave surface-wave assisted plasma enhanced chemical vapor deposition for the purpose of improving their barrier properties. Oxygen （O2） and hexamethyl- disiloxane （HMDSO） were employed as oxidant gas and Si monomer during SiOx deposition, re- spectively. Analysis by Fourier transform infrared spectroscope （FTIR） for chemical structure and observation by atomic force microscopy （AFM） for surface morphology of SiO~ coatings demon- strated that both chemical compounds and surface feature of coatings have a remarkable influence on the coating barrier properties. It is noted that the processing parameters play a critical role in the barrier properties of coatings. After optimization of the SiOx coatings deposition conditions, i.e. the discharge power of 1500 W, 2 ： 1 of O2 ： HMDSO ratio and working pressure of 20 Pa, a better barrier property was achieved in this work.     

射频磁控溅射法制备氧化铝涂层绝缘性能及吸氢特性

氧化铝具有优良的绝缘和阻氚性能,是ITER候选功能材料之一。本工作采用射频磁控溅射法在中国低活化马氏体（CLAM）钢基底上制备了氧化铝涂层。分别采用掠入射X射线衍射、Raman激光光谱和原子力显微镜对氧化铝涂层的结构和表面形貌进行了表征;测量了氧化铝涂层体电阻率;研究了氧化铝涂层样品的吸氢特性。结果表明：氧氩比为0.1和0.5下制备的氧化铝涂层为非晶结构,氧氩比为0.4下制备的涂层中出现了结晶程度较差的氧化铝δ相结构;氧氩比为0.1和0.4下制备的涂层粗糙度和粒径均小于氧氩比为0.5下制备的涂层;不同氧氩比下制备的氧化铝涂层体电阻率均超过2.7×10¹⁴Ω•cm,氧氩比为0.4下制备的涂层电阻率最高,达到2.1×10¹⁵Ω•cm;氧氩比为0.5下制备的涂层样品具有最低的吸氢量。氧氩比对涂层的电绝缘特性和吸氢特性有显著影响。     

Spatial Distribution of ECR Plasma Density in ECR-PECVD Reaction Chamber

The spatial distribution of Electron Cyclotron Resonance （ECR） plasma in the ECRPlasma Enhanced Metalorganic Chemical Vapour Deposition （ECR-PECVD） reaction chamber is diagnosed by a Langmuir probe. The uniformity is also investigated. The results show that the ECR plasma in the upper region of the reaction chamber under the influence of magnetic field has poor radial and axial uniformity. However, the plasma in the downstream region of the reaction chamber has fine radial uniformity. This excellent uniform plasma in the downstream has extensive application in plasma process.     

Heat Transfer During Radio Frequency Inductively Coupled Plasma Deposition of Tungsten

Particle melting and substrate temperature are important in controlling deposited density and residual stress in thermal plasma deposition of refractory materials. In this paper, both the heating and cooling behaviours of tungsten particles inside a radio frequency inductively coupled plasma （ICP） and the plasma heat flux to the substrate were investigated. The distribution of the plasma-generated heat on device, powder injection probe, deposition chamber, and substrate was determined by measuring the water flow rate and the flow-in and flow-out water temperatures in the four parts. Substrate temperature was measured by a two-colour pyrometer during the ICP deposition of tungsten. Experimental results show that the heat flux to the substrate accounts for about 20% of the total plasma energy, the substrate temperature can reach as high as 2100 K, and the heat loss by radiation is significant in the plasma deposition of tungsten.     

Saturation Ion Current Densities in Inductively Coupled Hydrogen Plasma Produced by Large-Power Radio Frequency Generator

An experimental investigation of the saturation ion current densities(Jions) in hydrogen inductively coupled plasma(ICP) produced by a large-power(2-32 kW) radio frequency(RF) generator is reported,then some reasonable explanations are given out.With the increase of RF power,the experimental results show three stages:in the first stage(2-14 kW),the electron temperature will rise with the increase of RF power in the ICP,thus,the J_(ions) increases continually as the electron temperature rises in the ICR In the second stage(14-20 kW),as some H~- ions lead to the mutual neutralization(MN),the slope of J_(ions) variation firstly decreases then increases.In the third stage(20-32 kW),both the electronic detachment(ED) and the associative detachment(AD) in the ICP result in the destruction of H~- ions,therefore,the increased amplitude of the J_(ions) in the third stage is weaker than the one in the first stage.In addition,with the equivalent transformer model,we successfully explain that the J_(ions) at different radial locations in ICP has the same rule.Finally,it is found that the J_(ions) has nothing to do with the outer/inner puffing gas pressure ratio,which is attributed to the high-speed movement of hydrogen molecules.     

The Effect of Plasma Surface Treatment on a Porous Green Ceramic Film with Polymeric Binder Materials

To reduce time and energy during thermal binder removal in the ceramic process, plasma surface treatment was applied before the lamination process.The adhesion strength in the lamination films was enhanced by oxidative plasma treatment of the porous green ceramic film with polymeric binding materials.The oxygen plasma characteristics were investigated through experimental parameters and weight loss analysis.The experimental results revealed the need for parameter analysis,including gas material,process time,flow rate,and discharge power,and supported a mechanism consisting of competing ablation and deposition processes.The weight loss analysis was conducted for cyclic plasma treatment rather than continuous plasma treatment for the purpose of improving the film’s permeability by suppressing deposition of the ablated species.The cyclic plasma treatment improved the permeability compared to the continuous plasma treatment.     

Effect of Frequency and Power of Bias Applied to Substrate on Plasma Property of Very-High-Frequency Magnetron Sputtering

The effect of the frequency and power of the bias applied to the substrate on plasma properties in 60 MHz(VHF) magnetron sputtering was investigated.The plasma properties include the ion velocity distribution function(IVDF),electron energy probability function(EEPF),electron density n_e,ion flux Γ_i,and effective electron temperature T_(eff).These parameters were measured by a retarding field energy analyzer and a Langmuir probe in the 60 MHz magnetron sputtering,assisted with 13.56 MHz or 27.12 MHz substrate bias.The 13.56 MHz substrate bias led to broadening and multi-peaks IVDFs,Maxwellian EEPFs,as well as high electron density,ion flux,and low electron temperature.The 27.12 MHz substrate bias led to a further increase of electron density and ion flux,but made the IVDFs narrow.Therefore,the frequency of the substrate bias was a possible way to control the plasma properties in VHF magnetron sputtering.     

Structure and Tribology Property of Carbon Nitride Films Deposited by MW-ECR Plasma Enhanced Unbalanced Magnetron Sputtering

Carbon nitride films were deposited by a twinned microwave electron cyclotron resonance （ECR） plasma source enhanced unbalanced magnetron sputtering system. The results indicate that the structure of the films is sensitive to the nitrogen content. The increase in the nitrogen flow ratio leads to an increase in the sp3 content and an improvement of the tribological properties.