17×17 硅基聚合物信道箱形光谱阵列波导光栅的制备

Arrayed waveguide grating (AWG) is a key device in wavelength-division multiplexing (WDM) system, and the flat spectral response of the AWG device is required. In this paper, the RIE process has been improved. By using the steam- redissolution technique, the insertion loss and the crosstalk have been reduced. Experimental results show that the central wavelength is 1550.86nm, and 3-dB bandwidth is about 0.478 nm, insertion loss is 10.5 dB, crosstalk is about –22 dB. The insertion loss of an AWG device is reduced by about 3 dB for the central channel and 4.5 dB for the edge channels, and the crosstalk is reduced by 2.5 dB after the steam- redissolution.     

AN INVERSE DESIGN OF ELECTROSTATIC FOCUSING FIELD FOR ELECTROSTATIC AND MAGNETIC IMAGING

An inverse design of electrostatic focusing field for electrostatic and magneticimaging is investigated.Using the potential superimposition theorem of electrostatic field inmulti-electrode system,a mathematical model has been developed and an optimization methodhas been introduced into computation for designing the electrostatic focusing field of the imagingsystem.     

W波段增益为25.7 dB两级cascode放大器

AW-bandtwo-stageamplifierMMIChasbeendevelopedusingafullypassivated 2 × 20 μm gate-width and 0.15 μm gate-length InP-based high electron mobility transistor （HEMT） technology. The two-stage amplifier has been realized in combination with a coplanar waveguide technique and cascode topology, thus leading to a compact chip-size of 1.85 × 0.932 mm^2 and an excellent small-signal gain of 25.7 dB at 106 GHz. Additionally, an inter-digital coupling capacitor blocks low-frequency signal, thereby enhancing the stability of the amplifier. The successful design of the two-stage amplifier MMIC indicates that InP HEMT technology has a great potential for W-band applications.     

Design and fabrication of ultrasmall arrayed waveguide grating multiplexers based on Si nanowire waveguides

In the past decades, integrated optical devices based on planar lightwave circuits (PLCs) have been developed rap- idly and used in various areas, such as optical communications, optical sensing and, etc. Because of their excellent performances and the feasibility for massive productions, PLC-based integrated optical devices may take the place of discrete devices more and more in the future. In order to satisfy the increasing demands of the optical net- works with a large capacity and high s…     

Graph theory for FPGA minimum configurations

A traditional bottom-up modeling method for minimum configuration numbers is adopted for the study of FPGA minimum configurations.This method is limited if a large number of LUTs and multiplexers are presented. Since graph theory has been extensively applied to circuit analysis and test,this paper focuses on the modeling FPGA configurations.In our study,an internal logic block and interconnections of an FPGA are considered as a vertex and an edge connecting two vertices in the graph,respectively.A top-down modeling method is proposed in the paper to achieve minimum configuration numbers for CLB and IOB.Based on the proposed modeling approach and exhaustive analysis,the minimum configuration numbers for CLB and IOB are five and three,respectively.     

使用GaAs MMIC技术的X波段微波频率检测器

The design, fabrication, and experimental results of an MEMS microwave frequency detector are presented for the first time. The structure consists of a microwave power divider, two CPW transmission lines, a microwave power combiner, an MEMS capacitive power sensor and a thermopile. The detector has been designed and fabricated on GaAs substrate using the MMIC process at the X-band successfully. The MEMS capacitive power sensor is used for detecting the high power signal, while the thermopile is used for detecting the low power signal. Signals of 17 and 10 dBm are measured over the X-band. The sensitivity is 0.56 MHz/fF under 17 dBm by the capacitive power sensor, and 6.67 MHz / μV under 10 dBm by the thermopile, respectively. The validity of the presented design has been confirmed by the experiment.     

New Type of Y—junction Hybrid Polymer Wavequide Couplers

Optical couplers are the key components for signal distribution in optoelectronic transmitters and receivers.A new low-loss, large-angle Y-junction hybrid polymer optical coupler with an integrated microprism has been fabricated and demonstrated experimentally for use in a mixed-signal module environment.The results show that the radiation loss is small with relatively wide branching angle as compared to a conventional Y-junction coupler.     

Solar light assisted photocatalysis of water using a zinc oxide semiconductor

The photocatalytic decomposition of an eco-persistent AO7 dye with sunlight in an oxygenated aqueous suspension has been studied under a nano-crystalline hexagonal ZnO photocatalyst.The effect of substrate temperature on the structural,morphological and photoactive properties has been investigated.The degradation of the A07 dye is achieved using a photoelectrochemical reactor module equipped with ZnO synthesized electrodes. Kinetic parameters have been investigated in terms of a first order rate equation.The rate constant for this heterogeneous photocatalysis was evaluated as a function of the initial concentration of original species.A substantial reduction in A07 dye is achieved as analyzed from COD and TOC studies.The mechanism for the degradation could be explained on the basis of the Langmuir-Hinshelwood mechanism.     

Research on Signal Processing Arithmetic of Subsurface Ground Penetrating Radar

Ground penetrating radar (GPR) is an impactful detection method of buried targets developed in these decades and has been broadly used in the world. Compared with other detection method, for example, resistivity, EMI and seismology, the GPR has many advantages. For this reason, the GPR is always one of the researching hotspots in the world in these years and has become an important branch of remote sensing. Although the design of GPRs is very complex and difficult, the demands of applications from different fields are continuously increasing. It is obvious that the research of GPR is very significant for the development of civil economy.     

Characterization and optimization of copper chemical mechanical planarization

The feature scale planarization of the copper chemical mechanical planarization (CMP) process has been characterized for two copper processes using Hitachi 430-TU/Hitachi T605 and Cabot 5001/Arch Cu10K consumables. The first process is an example of an abrasive-free polish with a high-selectivity barrier slurry, while the second is an example of a conventional abrasive slurry with a low-selectivity barrier slurry. Copper fill planarization has been characterized for structures with conformal deposition as well as with bumps resulting from bottom-up fill. Dishing and erosion were characterized for several structures after clearing. The abrasive-free polish resulted in low sensitivity to overpolish and low saturation levels for dishing and erosion. Consequently, this demonstrated superior performance when compared to the International Technology Roadmap for Semiconductors (ITRS) 2000 roadmap targets for planarization. While the conventional slurry could achieve the 0.13-μm technology node requirements, the abrasive-free polish met the planarization requirements beyond the 0.10-μm technology node.     

Schottky diode for bipolar LSI's consisting of an impurity-controlled Si substrate and Al(2%Si) electrode

Circuit design conditions of Schottky diodes have been investigated and the fabrication method for diodes suitable for the conditions has been proposed for applications to bipolar LSI's, such as ECL RAM and Schottky TTL. It has been found that the desired Schottky diode for bipolar LSI's is not an ideal device from the theoretical point of view. Desired built-in voltage, ideal factor, series resistance, and junction capacitance for the Schottky diode have been estimated, respectively, for the bipolar RAM and Schottky TTL. A proposed Schottky diode consists of an impurity-concentration-controlled     

Nonlinear theory of long-range-interaction resonant generators

A nonlinear self-consistent theory has been developed for resonant electronic generators of long-range interaction. The theory has been under development for devices whose electrodynamic system has a high Q-factor and a sufficiently rarefied spectrum. In accordance with the initial physical situation, the mathematical model under consideration has been obtained in the form of a system of differential equations, and an algorithm for its numerical solution has been proposed. The maximum amplitude of the generated oscillations in an open cavity with a Gaussian distribution of the field has been calculated analytically.     

Modeling of power supply noise in large chips using the circuit-based finite-difference time-domain method

In this paper, a multilayered on-chip power distribution network consisting of two million passive elements has been modeled using the finite-difference time-domain (FDTD) method. In this method, a branch capacitor has been used. The use of the branch capacitor is important for simulating multilayered power grids. In addition, a method for including the CMOS inverter characteristics into the FDTD simulation has been presented. As an example of the application of this method, an H-tree clock network was simulated to compute the power supply noise distribution across an entire chip. Various scenarios with varying decoupling capacitances, load capacitances, number of clock buffers, and rise times have been analyzed to demonstrate the importance of circuit nonlinearity on power supply noise. Also, a method has been presented for analyzing package and board planes. Based on the methods presented, the interaction between chip and package has been discussed for capturing the resonant behavior that is otherwise absent when each section of the system is analyzed separately.     

Optimized cooling systems for high-power semiconductor devices

Straightforward air cooling of semiconductor devices has gradually been replaced by methods using liquid coolants, especially water cooling. In this paper, more advanced cooling devices for hockey-puck-type and module-type semiconductors are suggested. An established heat sink made of aluminum nitride for the water cooling of hockey-puck-type semiconductors has been used as a basis for the development of high-performance heat sinks for increased heat flux densities. By means of thermal and fluid dynamics simulation tools the internal geometry has been optimized with regard to improved heat transfer and reduced pressure drop. The simulation results have been confirmed by a number of experiments using various measuring techniques. As an alternative cooling method for semiconductor modules, a modified baseplate comprising a number of fins for direct water cooling has been suggested. For an intelligent temperature management control algorithms have been developed, resulting in a prototype application-specific integrated circuit which has been implemented for test purposes     

Rectangular microstrip patch antennas with infinite and finite ground plane dimensions

The rectangular microstrip patch antenna has been extensively analyzed with regard to its input impedance and resonant frequency, both for infinite and finite ground plane dimensions. For infinite ground planes existing formulas have been compared and improved parameters presented. The influence from the side current radiation has been discussed as well. For finite ground plane dimensions the contribution from the ground plane edge diffraction has been accounted for in an equivalent radiation conductance and an equivalent diffraction susceptance. Formulas for these parameters have been developed on the basis of different theories. They are valid under the condition that only one of the ground plane dimensions are finite at the same time. Experimental investigations are carried out to test the accuracy of the developed formulas, showing good accuracy under the given conditions.     

Analysis of reflection coefficient for coated optical waveguide devices

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The Rudolf Kompfner Memorial Lecture†

In this paper an integrated method for minimization of switching functions is presented in which the generation and selection of prime implicants (PI) are interleaved. A method for generation of PI's incident on a given minterm has been described and a basis for selection or a PI as an element of the cover from a small subset of PI's has been established. The method presented for minimization of a completely specified switching function has also been extended for an incompletely specified switching function.     

On the barrier height of a metal-semiconductor contact with a thin interfacial layer

The free surface potential of a semiconductor has been studied by using a generalised definition of “neutral level.” Following this definition, an expression for the barrier height of an MIS structure has been derived, from which the expression for barrier height as derived by Cowley and Sze follows as a special case. Lastly, the formula used by previous workers for the determination of neutral level, has been modified for a more accurate calculation of the said parameter.     

Double-RESURF结构高压LDMOS模型

建立了Double-RESURF结构高压LDMOS器件的MOS VCR(Voltage Control Re-sistance)电路模型。通过分析Double-RESURF LDMOS器件的结构与输入输出特性,得到漂移区电阻的解析式;借助泰勒展式,得到VCR的高阶压控模型,从而建立LDMOS器件的SPICE模型。该模型的解析解和数值解符合良好,而且体现出高压LDMOS的准饱和特性。模型的建立可以很好地指导LDMOS器件的工程应用。     

Stochastic analysis of an Erlangian arrival with linear cost structure

In this paper a control policy for an Erlangian arrival has been studied. Here, the server goes on vacation when the system becomes empty, returning to an operative state after a random idle period lapses, or the queue length becomes N, whichever is earlier. The expressions for various operational characteristics have been obtained. Numerical results have been computed and some of these are graphed. Graphical interpretation of linear cost structure has been discussed.