Characterization method of thermomechanical parameters for microelectronic materials

Reliability of thermomechanical simulations is critically linked to the accuracy of the mechanical properties that govern the behaviour of structure, like Young's modulus (E) and coefficient of thermal expansion (CTE). For many cases, the values found in literatures are dealing with bulk properties without detailed information on temperature effects. To address such issues, it is necessary to measure the materials parameters as a function of temperature. The measurement of CTE is usually accomplished by evaluating the thermal deflections of a subjected material layer deposited on a substrate, providing that E is known at a specific temperature of experiment. A bilayer method, based on theory of elasticity, is proposed to determine both E and CTE for a given temperature with a good resolution. This paper presents the theoretical analysis, the design and process of the microsystem test structures, and the main calculation results.     

A hybrid neural network model for predicting silicon content

The silicon content of the hot metal in the blast furnace ironmaking process normally reflects the thermal state of the furnace and affects the fuel rate. In this paper a hybrid neural network model is proposed to predict the silicon contentn steps ahead. A time-delay neural network, which has self-loops to represent dynamics, is adopted here. The learning procedure of this network has been divided into two states. A BP algorithm with forgetting factor is first introduced to find the appropriate structure of the network. The temporal difference (TD) method with forgetting factor is then used forn-step-ahead prediction. The results show that the method can perform satisfactoryn-step-ahead prediction and is suited for implementation.     

高温处理对镍诱导晶化硅上的薄膜晶体管性能的影响

采用标准双栅 CMOS工艺在镍诱导非晶硅横向晶化形成的多晶硅上制造了高性能的薄膜晶体管 ,并详细研究了器件制备前高温预处理对薄膜晶体管性能的影响 .实验发现不同的温度处理 ,将引起器件性能的显著变化 .在10 0 0℃预处理温度下获得了最好的器件性能 .10 0 0℃在 NMOS管中测得的电子迁移率达 314 cm2 / (V· s) ,分别比在 110 0℃和未做高温处理下的大 10 %和 2 2 % .10 0 0℃下器件的最大开关电流比也达到了 3× 10 8.对器件的进一步重复性研究证实了上述结果的可靠性     

Polarization Extraction in Planar Near-Field Phaseless Measurements

Near-field measurements typically require both amplitude and phase information to correctly predict the far-field. Unfortunately, there are situations in which the phase data is not available or impractical to obtain. That is why there has been a need for the development of phaseless techniques. Up until now, a number of remarkable solutions to this problem have been proposed by the researcher in different disciplines. Unfortunately, the complete vectorial representation of the field is not investigated in depth. The evaluated cases are usually linearly polarized and only the dominant polarization is investigated while the cross polarized field is usually neglected. This paper addresses the polarization issue in a two-component approach and then proposes a solution to the problem. A searching mechanism, for the incorporation of an appropriate initial guess, is integrated into the well-known, iterative Fourier technique (plane-to-plane) to enhance the algorithm response. Then, using two sets of measured orthogonal information data gathered by two linearly and orthogonally polarized probes, it is shown that with the aid of only a single point amplitude measurement, the polarization characteristics of the antenna can be extracted up to an inherent ambiguity of the right- and left-handedness. In order to have an assessment of the applicability of the proposed method, both linearly and circularly polarized antennas are simulated. Additionally, the method of extracting the polarization from the phaseless data is also verified through a bi-polar near-field measurement.     

A Minimax Chebyshev Estimator for Bounded Error Estimation

We develop a nonlinear minimax estimator for the classical linear regression model assuming that the true parameter vector lies in an intersection of ellipsoids. We seek an estimate that minimizes the worst-case estimation error over the given parameter set. Since this problem is intractable, we approximate it using semidefinite relaxation, and refer to the resulting estimate as the relaxed Chebyshev center (RCC). We show that the RCC is unique and feasible, meaning it is consistent with the prior information. We then prove that the constrained least-squares (CLS) estimate for this problem can also be obtained as a relaxation of the Chebyshev center, that is looser than the RCC. Finally, we demonstrate through simulations that the RCC can significantly improve the estimation error over the CLS method.     

Hamilton-Jacobi skeleton on cortical surfaces

In this paper, we propose a new method to construct graphical representations of cortical folding patterns by computing skeletons on triangulated cortical surfaces. In our approach, a cortical surface is first partitioned into sulcal and gyral regions via the solution of a variational problem using graph cuts, which can guarantee global optimality. After that, we extend the method of Hamilton-Jacobi skeleton to subsets of triangulated surfaces, together with a geometrically intuitive pruning process that can trade off between skeleton complexity and the completeness of representing folding patterns. Compared with previous work that uses skeletons of 3-D volumes to represent sulcal patterns, the skeletons on cortical surfaces can be easily decomposed into branches and provide a simpler way to construct graphical representations of cortical morphometry. In our experiments, we demonstrate our method on two different cortical surface models, its ability of capturing major sulcal patterns and its application to compute skeletons of gyral regions.     

A simple CMOS process compatible high performance parallel-stacked spiral inductor for advanced RF analog circuit applications

A high Q on-chip inductor with some unique structures has been fabricated with 0.13 μm CMOS compatible process for the first time. The unique structures including parallel stacked, line via between inter-metal layers, and use the top signal pad as the under path of the inductor instead of conventional bottom signal pad. These structures offer advantages of reducing resistance, high Q value, simple preparing process and small chip area. Experimental results show that the measured peak Q and peak-Q frequency can attain 7.06 and 1.8 GHz, respectively for the structure with four metal layers in parallel, 15 μm in metal width, 5.5 turns in wire number,and an area of 204×240 μm². The results have a better potential for advanced mobile communication applications.     

InP optical switch array module high frequency performance: measurements and analysis

An injection-mode InP optical switch array has been characterised at high frequency. A switched optical pulse settling anomaly, which limits the switching performance of the array, is associated with recombination and junction heating effects at the switch heterojunction interface. A simple model describing the effects is presented. Critical design parameters are also identified.<>     

A high-density NAND EEPROM with block-page programming formicrocomputer applications

A high-density, 5-V-only, 4-Mb CMOS EEPROM with a NAND-structured cell using Fowler-Nordheim tunneling for programming is discussed. The block-page mode is utilized for high-speed programming and easy microprocessor interface. On-chip test circuits for shortening test time and for evaluating cell characteristics yield highly reliable EEPROMs. The NAND EEPROM has many applications for microcomputer systems that require small size and large nonvolatile storage systems with low power consumption