An Apparatus for the Production and Ion Bombardment of Thin Films†

This communication describes a versatile apparatus for the production of thin polycrystalline metallic films under conditions of high purity. The apparatus includes facilities for film preparation by evaporation and cathodic sputtering and for ion bombardment of the films under the same conditions of purity as obtained during preparation. The films can also be annealed before and after ion bombardment, although at this stage of the programme these facilities have not been fully used. Electrical conductivity measurements of the films can be made in situ and some preliminary data on the effects of ion bombardment on the electrical conductivity of thin metallic films are reported.     

沉积功率和气压对低频氮化硅薄膜应力的影响

利用等离子体增强化学气相沉积(PECVD)工艺,在不同射频功率,不同反应气压条件下制备了氮化硅薄膜。研究了低频工艺中氮化硅薄膜的沉积速率、应力以及厚度均匀性与其二者的关系。结果表明,射频功率的改变直接影响到离子对衬底的轰击效应,而反应气压的改变影响气体分子的平均自由程。离子轰击效应和分子平均自由程对氮化硅薄膜的生长过程产生影响,从而影响沉积速率、应力以及厚度均匀性等基本性质。     

Deposition Process Optimization of Zinc Oxide Films with Inclined Texture Axis

The optimization of technological parameters for fabrication of the inclined texture [0001] in ZnO films has been conducted. It is shown that the inclination of the texture axis is determined by at least two factors: the average vector of falling the deposited particles and the intensity of bombardment of the growing film with negative ions of oxygen. Optimum displacements of the substrate position relative to the axis of the sputtering system and the distance between the planes of the target and the substrate are determined. Films of zinc oxide with optimum angles of inclination of texture axis have been obtained by the RF sputtering technique.     

组分和应力不均匀分布对薄膜铁电性的影响

采用组合靶射频溅射的方法、制备后慢速降温的途径在（１１１）Ｓｉ基板上制备出了成膜较好的ＰｂＴｉＯ３薄膜，通过测试分析发现在薄膜中形成了一个缓解应力的过渡层，薄膜中的Ｐｂ、Ｔｉ组分比沿着薄膜生长的方向成非线性增长，并在薄膜表面形成一个富Ｐｂ层，薄膜的Ｃ－Ｖ特性曲线中存在负方向的位移和畸变。结合实验结果对薄膜的生长机理进行了探讨，并且对薄膜的应力和不均匀分布组分对薄膜铁电特性的影响进行了理论上的分析，     

Aging characteristics of AC plasma display panels

The initial accelerated aging ("burn-in") and the subsequent alternate-line-aging (ALA) characteristics of the operating voltages of ac plasma display panels were studied for MgO films deposited on dielectric glass substrates at 25°-350°C in a residual gas pressure of 10^-6-10^-7torr. To study the effects of the presence of oxygen during film deposition, the films were also deposited in 10^-4-10^-5torr of oxygen. Films deposited at 350°C showed significantly better aging characteristics than those deposited in 25°C. This observed dependence of the aging characteristics on the various parameters of the panel-fabrication process is explained in terms of a postulated effect of oxygen on the surface properties of MgO films and the changes in the surface properties of the MgO films (caused by changes in the surface stoichiometry) produced by ion bombardment during the discharge.     

Considerations on high resolution patterns engraved by ion etching

The theoretical model of a surface contour evolution under ion bombardment is applied to the study of the behavior of a mask during ion etching. Two new parameters are defined. The first gives an upper limit of the etching time when distortion-free patterns are needed. The second gives the lateral shift of the pattern if the previous limit is exceeded. Values of mask parameters were measured for various thin metal films under the following conditions: 1) Argon ion energy = 1 keV, 2) ion current density = 0.6 mA/cm², and 3) oxygen pressure in the sputtering chamber = 10^-4torr. It is shown that the introduction of oxygen improves the mask parameters.     

类金刚石碳膜在各种后处理条件下稳定行为的研究

本文介绍了类金刚石碳膜的结构和性能在高能离子束辐照、真空热退火及脉冲激光辐照等后处理条件下的变化特征,并就该膜在各种处理条件下的相变机制研究现状进行了评述。     

合成陨硫铁的扫描电镜观察

利用扫描电镜观察了不同反应条件下合成出的陨硫铁的颗粒形态。结果发现不同反应条件下合成出的陨硫铁大部分呈浑圆状集合体,少量呈香蕉状。在陨硫铁颗粒的断面上还可以发现气孔。根据以上结果,本文对陨硫铁的成因进行了初步的探讨,并就不同反应条件与陨硫铁的生长关系进行了研究。     

离子束增强沉积氮化硅薄膜生长及其性能研究

用离子束增强沉积技术合成了氮化硅薄膜并研究了薄膜的组分、性能和结构.结果表明,离子束增强沉积生长的氮化硅薄膜的组分比,可借助于调节氮离子和硅原子到达率之比加以控制.在合适条件下生长的氮化硅薄膜,其红外吸收特征峰在波数为840cm~(-1)附近,光折射率在2.2到2.6之间,其组分为Si_3N_4用RBS、AES、TEM、SEM、ED及扩展电阻,测量和观察生成的氮化硅薄膜的组分深度分布及结构.发现,离子束增强沉积制备的氮化硅薄膜,存在着表面富硅层、氮化硅沉积层及混合过渡层这样的多层结构.薄膜呈球状或方块状堆积.基本上是无定形相,但局部可观察到单晶相的存在.离子束增强沉积制备的氮化硅薄膜中的含氧量比不用离子束辅助沉积的显著减少.     

Effect of highly nonequilibrium conditions on the stoichiometry of cadmium telluride layer obtained by vapor-phase condensation

The results of comparison studies of the stoichiometry of cadmium telluride epitaxial films synthesized from the vapor phase in equilibrium and highly nonequilibrium (on cooled substrates) conditions are reported. The data of X-ray microanalysis and atomic-absorption analysis of the films and the vapor phase are given. The stoichiometry of the films is found to increase with lowering the substrate temperature. It is shown that the films obtained in highly nonequilibrium conditions have the best crystal structure.     

Determination of the structural and optical characteristics of Cu2ZnSnS4 semiconductor thin films

The results of X-ray diffraction and optical studies of Cu₂ZnSnS₄ films produced by the flash evaporation of binary sulfide compounds under different technological conditions is reported. It is shown that it is possible to produce Cu₂ZnSnS₄ films, rather perfect in structural and optical respects, by choosing the optimal annealing temperatures at different Ar vapor pressures. The lattice parameters of the compounds are determined. The systematic shift in the photoluminescence bands under variations in the excitation level is established. It is found that the characteristics of the bands depend to a large extent on the annealing temperature, the Ar pressure during thermal treatment, and the resultant stoichiometry composition of the samples. It is shown that Raman studies and luminescence measurements can be used to assess the quality of the synthesized Cu₂ZnSnS₄ films and to obtain data on the energy structure of defects in the band gap.     

On the stability of the operating voltages of AC plasma display panel

It is shown that doping MgO films with a transition metal, such as nickel, results in a statistically significant improvement in the stability of the operating voltages of an ac plasma display panel. Experimental results can be explained in terms of the effect of excess oxygen in the films on their surface properties, and the changes in the surface properties produced by ion bombardment during the discharge.     

Parameters and composition of HBr plasma under the conditions of glow DC discharge

A model investigation of parameters and steady-state composition of the HBr plasma under conditions of a dc glow discharge (p = 30–250 Pa, i _d = 10–30 mA) is performed. The calculated data by the composition of the neutral and ion components of the plasma are obtained. It is found that the balance of neutral particles is largely formed by radical chain processes. It is shown that the dissociative adherence of electrons to HBr_{V > 0} does not exert a determining effect on the kinetics of the processes of the formation-loss of charged particles because of low concentrations of vibrationally excited molecules.     

Cl2/BCl3感应耦合等离子体GaN刻蚀侧壁形貌研究

基于感应耦合等离子体干法刻蚀技术,对采用Cl2/BCl3气体组分下GaN刻蚀后的侧壁形貌进行了研究。扫描电镜(SEM)结果表明,一定刻蚀条件下,刻蚀后GaN侧壁会形成转角与条纹状褶皱形貌。进一步实验,观察到了GaN侧壁转角形貌的形成过程;低偏压功率实验表明,高能离子轰击是GaN侧壁转角与条纹状褶皱形貌形成的原因。刻蚀过程中,掩蔽层光刻胶经过高能离子一段时间轰击后,其边缘首先出现条纹状褶皱形貌,并转移到GaN侧壁上,接着转角形貌亦随之出现并转移到GaN侧壁上。这与已公开发表文献认为的GaN侧壁条纹状褶皱仅由于掩蔽层边缘粗糙所引起而非刻蚀过程中形成的解释不同。     

The effects of titanium films on secondary electron emission phenomena in resonant cavities and at dielectric surfaces

The phenomenon of electron bombardment heating of insulators in vacuum under the influence of RF fields by several types of multipactor processes is reviewed. Evidence is given to show that a practical way of limiting the electron bombardment of insulators is to provide surfaces which have a maximum secondary electron emission yield of less than one on both the insulator and on the related metal surfaces. Thin films of titanium metal are shown to have a very good effect on suppressing the secondary electron multiplication processes at both the metal and dielectric. The discontinuous nature of very thin metal films makes it possible to coat dielectrics with titanium with thicknesses sufficient to reduce the secondary emission yield without adding significantly to the loss factor or to the dc conductivity.     

溶胶-凝胶法合成光子晶体材料

用溶胶凝胶方法, 在碱性催化剂的作用下, 将正硅酸乙脂在乙醇与水的混合溶剂中水解, 获得了光子晶体材料, 即形状完美的二氧化硅球状颗粒。扫描电子显微镜和激光粒度仪分析表明, 所合成的产物为大小约0.7 μm的二氧化硅球状颗粒, 它们能够在玻璃衬底上自动排列成光子晶体。氦氖激光衍射实验表明, 由二氧化硅球状颗粒制成的光子晶体能够对红光产生11级衍射。当一束白光经过二氧化硅光子晶体时, 观测到了六重对称衍射花样, 表明二氧化硅球状颗粒在光子晶体中是六角紧密堆积结构。     

High-yield synthesis of silicon nanoparticles via the perpendicular pulsed laser ablation in the inert gas

Si nanoparticles are synthesized at a high rate(400-500 mg/h) using the perpendicular pulsed laser ablation(PPLA) on the silicon target at room temperature in Ar atmosphere.The PPLA method can also be used to obtain Si nanocrystal films with large areas on the glass substrate.These particles are etched with a mixture of hydrofluoric acid(HF) and nitric acid(HNO3) to reduce their sizes and the surfaces of these particles are passivated by the high-pressure water vapor annealing(HWA).After treatin...     

CeO_2高K栅介质薄膜的制备工艺及其电学性质

研究了 Ce O2 作为高 K (高介电常数 )栅介质薄膜的制备工艺 ,深入分析了衬底温度、淀积速率、氧分压等工艺条件和利用 N离子轰击氮化 Si衬底表面工艺对 Ce O2 薄膜的生长及其与 Si界面结构特征的影响 ,利用脉冲激光淀积方法在 Si(10 0 )衬底生长了具有 (10 0 )和 (111)取向的 Ce O2 外延薄膜 ;研究了 N离子轰击氮化 Si衬底表面处理工艺对 Pt/ Ce O2 / Si结构电学性质的影响 .研究结果显示 ,利用 N离子轰击氮化 Si表面 /界面工艺不仅影响 Ce O2 薄膜的生长结构 ,还可以改善 Ce O2 与 Si界面的电学性质     

Investigation of the role of charged species in hot filament assisted CVD of diamond

Low pressure formation of diamond is well known, and has been accomplished by activating hydrocarbon/hydrogen mixtures near a heated substrate by means of a hot filament, dc glow discharge, etc. Many researchers have reported that externally applied voltages strongly affect the CVD process, and this is often attributed to electron bombardment effects. For this work, a filament assisted CVD reactor was modified by placing a grid between the filament and substrate, enabling independent control of the substrate potential and the filament to substrate current. Growth experiments under various bias conditions indicate that negatively charged species participate in the growth process, and that the reaction rate depends on the substrate potential. The growth rate becomes negligible when the substrate is held at a negative potential, even in the presence of a large current, which calls into question the electron bombardment explanation of the growth rate dependence on electrical bias.     

Influence of the samarium impurity on the structure and surface morphology of Se<Subscript>95</Subscript>Te<Subscript>5</Subscript> chalcogenide glassy semiconductor

X-ray diffraction and atomic-force microscopy are used to study the structure and surface morphology of Se₉₅Te₅ chalcogenide glassy semiconductor films and the influence exerted on these films by doping with samarium. The parameters of the first sharp diffraction peak (FSDP), observed in X-ray diffraction patterns, are used to determine the numerical values of the local structure parameters, such as the “quasiperiod” of density fluctuations, correlation length [size of medium-range-order (MRO) regions], and nanovoid diameters. In addition, the numerical values of the roughness-amplitude parameters are determined. It is found that the disorder in the atomic structure and the irregularities on the surface of the films under study become more pronounced with increasing percentage content of the samarium impurity.