Metalorganic chemical vapor deposition of silver thin films for future interconnects by direct liquid injection system

Deposition of Ag films by direct liquid injection-metal organic chemical vapor deposition (DLI-MOCVD) was chosen because this preparation method allows precise control of precursor flow and prevents early decomposition of the precursor as compared to the bubbler-delivery. Silver(I)-2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedionato-triethylphosphine [Ag(fod)(PEt₃)] as the precursor for Ag CVD was studied, which is liquid at 30 °C. Ag films were grown on different substrates of SiO₂/Si and TiN/Si. Argon and nitrogen/hydrogen carrier gas was used in a cold wall reactor at a pressure of 50–500 Pa with deposition temperature ranging between 220 °C and 350 °C. Ag films deposited on a TiN/Si diffusion barrier layer have favorable properties over films deposited on SiO₂/Si substrate. At lower temperature (220 °C), film growth is essentially reaction-limited on SiO₂ substrate. Significant dependence of the surface morphology on the deposition conditions exists in our experiments. According to XPS analysis pure Ag films are deposited by DLI-MOCVD at 250 °C by using argon as carrier gas.     

Barrier layer effect of tantalum on the electromigration in sputtered copper films on hydrogen silsesguioxane and SiO2

As IC devices scale down to the submicron level, the resistance-capacitance (RC) time delays are the limitation to circuit speed. A solution is to use low dielectric constant materials and low resistivity materials. In this work, the influence of underlying barrier Ta on the electromigration (EM) of Cu on hydrogen silsesquioxane (HSQ) and SiO₂ substrates was investigated. The presence of a Ta barrier not only improves the adhesion between Cu and dielectrics, but also enhances the crystallinity of Cu film and improves the Cu electromigration resistance. The activation energy obtained suggests a grain boundary migration mechanism and the current exponent calculated indicates the Joule heating effect.     

钨金属化与氧化铝陶瓷高温共烧

阐述了钨金属化与氧化铝陶瓷高温共烧工艺的特点,分析了烧结过程中温度曲线和露点等工艺参数对钨金属化与瓷件结合强度、密封气密性和收缩率的影响。通过反复的试验和烧结机理分析对比,给出了最佳的控制参数。     

用基函数神经网络实现多阈值图象分割

本文介绍了一种用基函数神经网络实现多阈值图象分割的新方法。它从函数逼近的角度研究基于灰度直方图的多阈值分割问题，提出了一种模糊反向传播学习算法，采用该算法的高斯基函数网络能够准确检测直方图中包含的子区域和它们的分布函数，而且速度很快。实验表明本文的方法在实际图象分割中是有效的。     

级联型多电平逆变器中多载波PWM控制方法的改进

级联型多电平逆变器由于其模块化结构、便于生产高度、更换容易等特点，受到电力电子工程技术人员的广泛关注。本文通过对于级联型多电平逆变器几种典型的控制方法的分析比较，提出了一种改进多载波PWM控制方法。该方法通过改变载波的幅值，使级联逆变器的各个逆变单元开关规律相同，并使所有的开关器件的损耗一致，有利于逆变单元的统一设计和可靠运行。     

Ein lösbarkeitskriterium für ein mehrstufen – mehrsorten – transportproblem

A variant for checking a solvability eriterion for multilevel multisort transportation problem is given.     

New antenna design approach – 3D polymer printing and metallization. experimental test at 14–18 GHz

This paper proves a new approach for rapid prototyping of radio antennas through 3D printing and chemical metallization. For this purpose, a standard metal pyramidal horn prototype is compared with its 3D printed replica. Three different 3D polymer printers are tested. The printed samples are assessed nondestructively by an X-ray Industrial Computed Tomography (CT) scanner, and then metalized via chemical deposition and chemical-electrochemical deposition. Copper with two different layer thicknesses and nickel materials are deployed and verified as a metallization opportunity. Again the CT scanner, X-ray fluorescent analysis and nanoindentation technique were used to perform the metallization quality estimation. As a result, a qualitative polymer prototype was produced having weight of 13 g – ten times lighter than the original. The prototype was successfully metalized and was able to be soldered. The radio-measurement comparison with the metal original for frequencies 14–18 GHz showed no significant differences. Finally, a simple dynamometric test confirmed the bonding between the metal and the polymer. To the best of our knowledge this is the first known comprehensive analysis of the possibility to print 3D lightweight wideband polymer antenna prototypes with a stable chemical metallization and radio properties very close to the original at 14–18 GHz.     

Optimization of Direct Blue 71 sorption by organic rich-compost following multilevel multifactor experimental design

Removal of a troublesome textile dye, Direct Blue 71 (DB71) from water by a food waste compost was assessed in the current study. Since compost dye sorption is a multi-factor process influenced by mass, pH, concentration, temperature, contact time, and salinity, the cumulative influence of all parameters on DB71 removal was examined following an optimal multilevel multifactor experimental design. The process had to be presented using both linear and interaction terms, according to the variables analysis: Dye sorption = –0.050Mass + 0.122Conc–0.114pH + 0.132Time – 0.074Temp + 0.056Sal + 0.103Mass × Conc + 0.226 Mass × pH – 0.257Mass × Time – 0.112Mass × Temp – 0.041Mass × Sal + 0.008Conc × pH + 0.100Conc × Time + 0.089Conc × Temp + 0.167Conc × Sal – 0.245pH × Time – 0.231pH × Temp – 0.123pH × Sal + 0.358Tim × Temp + 0.355Tim × Sal – 0.045Temp × Sal (R² = 0.9241)Salinity and pH were positively correlated with concentration, and contact time with temperature and salinity, to get better dye uptake. The optimal conditions for dye removal were the following: solid:liquid ratio 1:375, pH 3.0, initial dye concentration 400 mg L^?1, contact time 240 min, salinity 0.6 M NaCl, temperature 50 °C. At the optimum combination of factors, equilibrium sorption isotherm and sorption kinetics were studied. Kinetic analysis indicated high sorption rate 4.0 mg g^?1 min^?1 while 28% of maximum capacity was reached within the first 10 min of interaction. Sorption isotherm has L2-shape which reflected surface saturation at high solute concentration with low competition with solvent molecules, with a maximum sorption capacity of 95.4 mg g^?1. In column experiments performed at bed depth 5.1–12.8 cm, flow rate 1.0–2.0 mL min^?1 and influent concentration 10–20 mg L^?1, sorption capacity was 19.6 mg g^?1, which represents 21% of the maximum capacity at equilibrium conditions. IR analysis of dye-loaded-compost confirmed the contribution of hydrophobic-hydrophobic forces in the sorption process.     

高速脊波导激光器寄生电容的分析

高速调制半导体激光器光源是光纤通信系统、相控阵雷达等的关键器件。高速激光器的寄生电容是影响其调制带宽的因素之一。为了减小寄生电容,针对脊波导结构激光器的电容,采用计算机模拟与实际测试相结合的方法,进行了理论分析和实验验证。结果表明,其寄生电容大小不仅与电极金属化面积有关,还与隔离沟的腐蚀深度有关。当腐蚀至波导层时,寄生电容减小到10pF以下。这一结论对实现激光器的高速调制是非常有意义的。