Deposition of copper films by unbalanced d.c. magnetron sputtering

The electrical resistivity of as deposited polycrystalline copper thin films as a function of varying the process parameters has been investigated. Trying to minimize the resistivity of the copper thin films is important in the semiconductor industry, due to the fact that low resistivity copper can be employed to great advantage for new metallization schemes in advanced ultralarge scale integrated circuits. This paper presents the optimum choice of parameters that are necessary to achieve low resistivities of the thin films in reproducible experiments. All the depositions were performed using an unbalanced d.c. planar magnetron sputtering source (consisting of a circular copper target (98% purity, 0.01% Fe, 0.005% Ni, 0.005% Si) with a diameter of 100mm fitted with two electromagnets). The copper thin films were deposited onto glass substrates with argon being used as the sputtering gas. The resistivity was studied as a function of the pressure of the sputtering gas, the substrate bias, the substrate to target distance, the magnetron power, and the substrate temperature. It was found that depositions producing thin films with a resistivity of that approaching the bulk material (1.7×10^–8m) were obtained if the sputtering gas pressure was below 0.2 Pa. The effect of the substrate bias was insignificant at these pressures. The crystallographic structure of the copper thin films, determined by X-ray diffraction, is also reported.The authors would like to thank Dr. Soukup for his support during this research. We would also like to express our gratitude to Mr. A. Rajský for improving the design of the sputtering device. This work was partially financed by a grant from the Grant Agency of the Czech Republic No. 202/93/0508.     

Mathematical model of the dynamics of micropolar elastic thin beams. Free and forced vibrations

A method of hypotheses has been developed to construct a mathematical model of micropolar elastic thin beams. The method is based on the asymptotic properties of the solution ofan initial boundary value problem in a thin rectangle within the micropolar theory of elasticity with independent displacement and rotation fields. An applied model of the dynamics of micropolar elastic thin beams was constructed in which transverse shear strains and related strains are taken into account. The constructed dynamics model was used to solve problems of free and forced vibrations of a micropolar beam. Free vibration frequencies and modes, forced vibration amplitudes, and resonance conditions were determined. The obtained numerical calculation results show the specific features of free vibrations of thin beams. Micropolar thin beams have a free vibration frequency which is almost independent of the thin beam size, but depends only on the physical and inertial properties of the micropolar material. It is shown for the micropolar material that the free vibration frequency values of beams can be readily adjusted and hence a large vibration frequency separation can be achieved, which is important for studying resonance.     

磁控反应溅射SiNx薄膜的研究

用磁控反应溅射(RF)的方法制备了SiN_x薄膜. 分析了以硅为靶材, 用N₂/Ar做溅射气体条件下不同的气流比率、总气压以及沉积速率对薄膜光学常数和表面结构形态的影响, 得出较低总气压下气流比率对薄膜光学常数的影响是最关键的, 而总气压较大的时候, 水汽影响增大, 气流比率的影响反而不明显. 最后提出了合适的工艺条件来制备符合要求的SiN_x薄膜.     

Quantum Transport. Introduction to Nanoscience,by Y.V. Nazarov and Y.M. Blanter

A brief review of the interstellar medium and its instabilities is given with particular emphasis to recent results on its “two-phase” nature. The existing models (both numerical and analytic) of the collapse of gas clouds to form stars are discussed; this discussion is divided into the optically thin and thick phases. Finally some aspects of the observations of young stars are considered.     

从薄膜波导传播衰减的角度研究光学薄膜的损耗:(Ⅱ)实验分析

本文从实验的角度介绍从薄膜导波传播衰减研究光学薄膜损耗的方法,并以一些低损耗的光学薄膜样品的测量结果说明这种方法对损耗研究的灵敏程度及其优越性.     

Synthesis of nano ZnO thin film on Al foil by rf glow discharge plasma and its effect on E. coli and P. aeruginosa

Nano ZnO thin films were deposited on thin Al foils by a rf glow discharge plasma method in which sublimed zinc acetate vapor (precursor) reacted with oxygen plasma inside a low-pressure reactor. The films were microstructurally characterized using XRD, TEM, FESEM, optical reflectance and micro-Raman spectroscopy methods. In view of the good scope of ZnO coating in food packaging, the antibacterial activity in the ZnO thin films was studied by exposing the films to E. coli and P. aeruginosa for up to 8 h. Bacterial cell inhibition of up to 98–99 % was observed in the thin films.     

Observation of surface modes in S.W.R.

We wish to report the unambiguous observation of surface modes in spin wave resonance in thin metal films. These surface modes, as predicted by Puszkarski are shown to be evident in both the parallel and perpendicular field configurations.     

外加磁场对磁控溅射制备氮化硅陷光薄膜的影响

在基底与靶材之间放置磁性强弱不同的永久磁铁来研究外加磁 场对磁控溅射制备氮化硅陷光薄膜的影响. 通过X射线衍射、原子力显微镜 (AFM) 以及紫外分光光度计分别测试了外加磁场前后所制备薄膜的组织结构、表面形貌和光学性能. 结果表明, 外加磁场后, 氮化硅薄膜依然呈现非晶结构; 但是表面形貌发生明显改变, 中心磁场1.50 T下, 薄膜表面为特殊锥状尖峰结构"类金字塔"的突起, 而且这些突起颗粒垂直于基底表面; 在 可见光及近红外范围内, 中心磁场1.50 T 下的薄膜样品平均透射率最大, 平均透射率达到90% 以上, 比未加磁场的样品提高了近1 倍, 具有很好的陷光特性. 关键词： 外加磁场 磁控溅射 氮化硅薄膜 陷光效应     

Thin prism refraction. A new direct method of polariton spectroscopy

Refraction of light by thin prisms has been used for the first time to obtain dispersion curves of excitonic polaritons. This most direct method demonstrated here for the A- and B-exciton in thin prismatic CdS crystals is shown to be extremely precise in spite of its simplicity. Improved values of polariton parameters are reported. In the mixed mode orientation we observed birefringence due to spatial dispersion. This opens a way to study the problem of additional boundary conditions.     

Investigation of CdTe films with Fe,in and Sb impurities produced by R.F. sputtering technique

We report here the preliminary results on CdFeTe with indium and antimonium thin films. The population of Fe²⁺ increases linerly with the alitimonium content in FeCdTe thin films and this results in a less crystallized material. Indium, on the other hand, has a less pronounced effect on the Fe²⁺/Fe³⁺ population.     

Second-Harmonic Generation from a Thin Cylindrical Layer. I. An Analytical Solution

Optics and Spectroscopy - The problem of second-harmonic generation by a plane elliptically polarized electromagnetic wave from a thin optically nonlinear layer on the surface of a cylindrical...     

The enhancement of dark d.c. conductivity by gas adsorption on thin films of macrocyclic copper complexes

The dark d.c. conductance of thin films of copper complexes of phthalocyanine (α-form), hemiporphyrazine and dihydrodibenzo [b, i] [1, 4, 8, 11] tetra-azacyclotetradecine has been studied in vacuo and in the presence of an extensive range of gases. Only those gases which can be classed as electron acceptors increased the conductance, with NO₂/N₂O₄ (“NOX”) being particularly effective. Spectroscopic evidence is provided to show that the NOX-copper phthalocyanine interaction generates the organic radical cation and NO^-₂, and that substantial quantities of gas are accumulated within the thin film. A new class of extrinsic organic semiconductor is described.     

Calculating acoustical properties of cells: influence of surface topography and liquid layer between cell and substrate.

In this paper, a mathematical formulation is presented to compute the V(z) of a tapering layered solid and applying this formulation to the determination of acoustic properties of biological cells and tissues. The formulation is adopted in the simplex inversion algorithm to obtain the acoustic properties of a tapering cell from its V(z) values. The influence of two parameters had been considered: The tapering angle and the presence of a thin liquid layer present between cells and the substratum to which they adhere. Up to a tapering angle less than 10 degrees, it can be safely neglected. However, if a larger angle is neglected, then the acoustic wave velocity in the cell is overestimated. Cell thickness estimation is not affected significantly when the tapering angle is ignored. The calculations of acoustic properties of cells are considerably influenced by the introduction of a thin fluid layer between the solid substratum and the overlying cell, neglecting the presence of at least a very thin layer (20-30 nm), in general, results in a considerable overestimation of sound velocity. The reliability of the data calculated from V(z) values was ascertained using an independent method to determine cell thickness by calculating it from the interference fringe pattern obtained with the reflection-interference light microscope. The shape of the glutaraldehyde-fixed cells was similar to fried eggs. The highest sound velocities were found close to the periphery of the dome-shaped cell center. In the very center and over most of the area of the thin periphery, sound velocity was close to that in saline.     

Sum-Frequency Generation from a Thin Spherical Layer: II. Analysis of Solution

We have analyzed the influence of the angle between the wave vectors of two incident waves (the opening angle) and of the type of the anisotropy of a nonlinear layer on the shape of the directivity pattern of a sum-frequency harmonic generated by the two plane elliptically polarized electromagnetic waves from a thin spherical optically nonlinear layer deposited on the surface of a dielectric spherical particle placed in a dielectric. Our analysis has shown that, if the radius of the thin spherical nonlinear layer is small, the shape of the directivity pattern will change significantly with increasing opening angle only for some types of anisotropy: the main lobes shift toward the direction that is opposite to the direction of the sum of the wave vectors of the incident waves. For three types of anisotropy, the directivity patterns have similar shapes. We have also found that, for one of the types of the anisotropy, the shape of the directivity pattern remains unchanged upon a change in the opening angle. The mathematical properties of functions describing the spatial distribution of the generated harmonic have been determined. In particular, it has been found that, upon incidence of linearly polarized waves on a thin nonlinear spherical layer that possesses either solely chiral or solely nonchiral nonlinear properties, linearly polarized radiation of the sum-frequency harmonic is generated.     

ALNx thin films produced by d.c. reactive magnetron sputtering

Conclusion Aluminium nitride is the very promising thin film material for piezoelectric /2,3/ and microelectronic /4,5/ applications. The high microhardness of AlN_X films, verified in our experiment, opens new possibilities of practical utilization of these films.We wish to thank O.Pártl of the Department of Materials of the Faculty of Nuclear Science and Physical Engineering in Prague for help with microhardness measurements.     

Collisional — Radiative Model of Helium Plasma. I. Description of the Model

We present a collisional-radiative model of helium plasma with explicit inclusion of metastable state influences and give results of numerical calculations of population coefficients and effective reaction rates (generalization of effective ionization and recombination coefficients for the case when metastable states are not explicitly included) for a large region of electron densities and temperatures for optically thin and thick helium plasma. The model is described in this paper.     

射频溅射微晶NiOxHy膜电致变色性能及其机理研究

研究了射频溅射制备的NiO_x膜的电致变色性能,发现富氧非理想化学配比的NiO _x(x>1)膜具有变色活性,这种膜出现Ni³⁺和Ni²⁺的混 合价态,当H^＋注入并占据Ni空位时,导致Ni³⁺的t_2g 能级被填满,Ni³⁺被阴极还原为Ni²⁺引起光学透明,即为漂白态; 反之,H⁺被萃取出NiO 关键词： xH_y膜')" href="#">NiO_xH_y膜 电致变色     

A study of the metal-ionic conductor interface capacitances. I. Experimental method

In the study of interface capacitances of metal-ionic conductor contacts, difficulties are often encountered to make a reference electrode. The samples used in this work have two blocking electrodes and a third one, located in the bulk of the ionic material. This arrangement is elaborated by successive depositions of gold, lead fluoride, and gold thin films. Each interface capacitance can be obtained from a frequency analysis of the three-probe system. The results show that the structure is not symmetrical, because of differences in the roughness of the electrodes.