High-performance MIM capacitor using ALD high-k HfO/sub 2/-Al/sub 2/O/sub 3/ laminate dielectrics

For the first time, we successfully fabricated and demonstrated high performance metal-insulator-metal (MIM) capacitors with HfO/sub 2/-Al/sub 2/O/sub 3/ laminate dielectric using atomic layer deposition (ALD) technique. Our data indicates that the laminate MIM capacitor can provide high capacitance density of 12.8 fF//spl mu/m/sup 2/ from 10 kHz up to 20 GHz, very low leakage current of 3.2 /spl times/ 10/sup -8/ A/cm/sup 2/ at 3.3 V, small linear voltage coefficient of capacitance of 240 ppm/V together with quadratic one of 1830 ppm/V/sup 2/, temperature coefficient of capacitance of 182 ppm//spl deg/C, and high breakdown field of /spl sim/6 MV/cm as well as promising reliability. As a result, the HfO/sub 2/-Al/sub 2/O/sub 3/ laminate is a very promising candidate for next generation MIM capacitor for radio frequency and mixed signal integrated circuit applications.     

用MATLAB进行三相交-交变频电源的仿真设计

三相交－交变频电源在低频拖动控制中有广泛的应用，通过晶闸管设计的静止式变频电源具有效率高，无噪声的优点，但却存在设计复杂、成本高，高速困难等缺点，而利用MATLAB软件中的Simlink仿真工具来实现三相交－交变频电源的仿真设计和分析，能做到省时，省成本，易于操作，在静止式变频电源设计中有很好的使用价值。采用MATLAB仿真工具完成了一个全数字控制的三相交－交变频电源的设计。     

基站智能天线多波束合成技术

采用数字波束形成的技术，给出了基站智能天线多波束合成的有效算法。对圆环阵分布的基站天线多波束方向图进行了综合，得到了空间隔离度很好的多个波束，并将副瓣控制在30dB以下，结果令人满意。该方法可用于任意单元构成的不均匀阵列天线，还可用于波束展宽及扇形波束的合成。     

Gamma-irradiation-induced Ag/SiO2 composite films and their optical absorption properties

Small Ag particles or clusters dispersed mesoporous SiO₂ composite films were prepared by a new method: First the matrix SiO₂ films were prepared by sol-gel process combined with the dip-coating technique, then they were soaked in AgNO₃ solutions followed by irradiation of γ-ray at room temperature and in ambient pressure. The structures of these films were examined by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and optical absorption spectroscopy. It has been shown that the Ag particles grown within the porous SiO₂ films are very small, and they are isolated and dispersed from each other with very narrow size distributions. With increasing the soaking concentration and an additional annealing, an opposite peakshift effect of the surface plasmon resonance (SPR) was observed in the optical absorption measurements.     

弹性-粘弹性复合结构随机响应的各阶谱矩的计算方法

提出了一种新的计算弹性-粘弹性复合结构随机响应的各阶谱矩的计算方法，它是一种时域复模态分析方法。利用此方法获得了弹性-粘弹性复合结构在白噪声、滤过白噪声等典型平稳随机激励下随机响应的各阶谱矩的解析表达式，分析了粘弹性对各阶谱矩的影响。此计算方法简便、易用，无论单自由度或多自由度系统均适用，为进一步研究弹性-粘弹性复合结构在随机激励下的可靠性打下良好基础。     

重复压裂气井产能模拟研究

由于重复压裂气井原有裂缝的失效程度难以评价。导致重复压裂气井的产能预测常常有很大的误差。为此，根据重复压裂气井的压前产量和舍水率，拟合了原有裂缝的有效率，在考虑新裂缝和原有裂缝共同作用的情况下，建立了气、水两相平面二维的裂缝-油藏数学模型，通过对模型的数值求解，对重复压裂气井进行了产能评价。研究表明，在考虑新、老裂缝共同作用下的产能评价方法，能更为准确地预测重复压裂后的生产动态情况，对压裂时机的确定、压后经济效益的预测都具有重要的指导意义。     

基于多抽样率信号处理的无源雷达MTD方法

以数字电视信号为机会照射源的雷达系统研究为背景 ,提出用以多抽样率信号处理为基础的多级抽取信号处理算法解决运动目标检测中海量数据处理问题。文中叙述了数字电视广播信号回波的数学模型、多级抽取基本原理、目标检测算法 ,以数字电视信号为反射回波做了仿真 ,对运动目标进行检测 ,并对仿真结果做了分析。     

Enhanced thermal stability of a sputtered titanium-nitride film as a diffusion barrier for capacitor-bottom electrodes

The effect of a thin RuO_x layer formed on the Ru/TiN/doped poly-Si/Si stack structure was compared with that on the RuO_x/TiN/doped poly-Si/Si stack structure over the post-deposition annealing temperature ranges of 450–600°C. The Ru/TiN/poly-Si/Si contact system exhibited linear behavior at forward bias with a small increase in the total resistance up to 600°C. The RuO_x/TiN/poly-Si/Si contact system exhibited nonlinear characteristics under forward bias at 450°C, which is attributed to no formation of a thin RuO_x layer at the RuO_x surface and porous-amorphous microstructure. In the former case, the addition of oxygen at the surface layer of the Ru film by pre-annealing leads to the formation of a thin RuO_x layer and chemically strong Ru-O bonds. This results from the retardation of oxygen diffusion caused by the discontinuity of diffusion paths. In particular, the RuO_x layer in a nonstoichiometric state is changed to the RuO₂-crystalline phase in a stoichiometric state after post-deposition annealing; this phase can act as an oxygen-capture layer. Therefore, it appears that the electrical properties of the Ru/TiN/poly-Si/Si contact system are better than those of the RuO_x/TiN/poly-Si/Si contact system.     

共面波导有限金属厚度效应的研究

用保角变换法对共面波导金属厚度效应进行了理论分析，编制了相应的计算机程序，给出了数值解，并对此进行了多元曲线拟合，导出了考虑金属厚度后的形状比k、有效介电常数、特征阻抗、损耗的闭定表达式。用此修正表达式求得特征阻抗及损耗的数值解，并与K．C．格普塔的修正值及实验测量值进行了详细比较，结果表明此修正公式与实验值相符较好。