一种新颖微机械数模转换器的模拟与设计优化

提出了一种基于权间隙原理的微机械数模转换器(WGDAC),它与电路中的权电阻数模转换器的原理类似,利用间隙的长度作为比例因子,从而实现由二进制电压输入到模拟位移输出的转换.给出了有限元方法分析对由热执行器阵列驱动的数模转换器的输出位移分析的结果.为了减小误差,对结构作了优化设计,使误差不大于0.002μm.     

基于权值的微机械数模转换器

提出了一种新颖的基于权值的微机械数模转换器 ,它的原理与电路中的权电阻数模转换器类似。通过改变纵向梁的长度获得不同的刚性值作为比例因子 ,从而实现由二进制电压输入到模拟位移输出的转换。为了减小误差 ,对结构作了优化设计 ,同时还考虑并解决了零稳定性问题 ,提高了输出位移的精度。文中给出了有限元方法对由热执行器阵列驱动的数模转换器的输出位移分析的结果 ,并对几种微机械数模转换器的设计进行了比较。     

静电驱动悬臂梁数模转换器设计、分析与模拟

提出了一种新型的微电子机械数模转换器 (MEMDAC)———静电驱动悬臂梁数模转换器 .与传统的静电驱动悬臂梁执行器相比 ,新的结构能更精确地控制梁的挠度 .文中给出了此MEMDAC的设计、分析和模拟过程 .有限元(FEA)分析表明此MEMDAC的最大输出位移为 1 5 1μm ,分辨率为 0 1μm ,其最大非线性误差为 0 0 3μm .     

一种用于数模转换器的电流-电压转换电路

介绍了一种用于数模转换器的电流 电压转换电路。在数模转换器的负载电阻片内集成的情况下 ,利用文中提出的电流 电压转换电路 ,数模转换器实现了要求的宽摆幅电平输出 (全“0”输入时 ,输出低电平 - 3V ;全“1”输入时 ,输出高电平 3 5V)。整个数模转换器电路用 1 2 μm双层金属双层多晶硅n阱CMOS工艺实现。其积分非线性误差为 0 4 5个最低有效位 (LSB) ,微分非线性误差为 0 2LSB ,满摆幅输出的建立时间小于 1μs。该数模转换器使用± 5V电源 ,功耗约为 30mW ,电路芯片面积为 0 4 2mm2 。     

基于线性调频信号的数模转换器时钟抖动误差分析

数模转换器的时钟抖动引起输出信号的误差,该误差会影响后继的信号处理.本文分析了数模转换器中输入为线性调频信号时,由时钟抖动引起的误差.首先给出了该误差平均功率表达式,然后根据该表达式推导出输出信噪比的近似计算公式,最后对影响信噪比的各种因素进行讨论,其中信号的带宽及时钟抖动参数的增大均会降低输出信噪比,而调频斜率的变化对输出信噪比影响较小,采样频率的增大可以在一定程度上提高信噪比.仿真结果验证了信噪比计算公式的正确性,并给出了信噪比随各种因素变化的趋势.     

静电驱动悬臂梁数模转换器设计、分析与模拟

提出了一种新型的微电子机械数模转换器(MEMDAC)--静电驱动悬臂梁数模转换器.与传统的静电驱动悬臂梁执行器相比,新的结构能更精确地控制梁的挠度.文中给出了此MEMDAC的设计、分析和模拟过程.有限元(FEA)分析表明此MEMDAC的最大输出位移为1.51μm,分辨率为0.1μm,其最大非线性误差为0.03μm.     

微机械数志换器的原理与应用

微机械数模转换器是一种用数字信号精确控制微执行器输出的新方法,本文介绍了微机械数模转换器的概念,分析了“C－2C梯型网络”,“逐级衰减”两种实现方案的基本原理和结构,对它们的误差,最大分辨率等特性进行了分析,最后对微机数模转换器应用领域和下一步的发展进行展望。     

高速SOIMOS器件及环振电路的研制

设计了一种 1 0位 50 MS/s双模式 CMOS数模转换器 .为了降低功耗 ,提出了一种修正的超前恢复电路 ,在数字图象信号输出中 ,使电路功耗降低约 30 % .电路用 1μm工艺技术实现 ,其积分线性误差为 0 .46LSB,差分线性误差为 0 .0 3LSB.到± 0 .1 %的建立时间少于 2 0 ns.该数模转换器使用 5V单电源 .在 50 MS/s时全一输入时功耗为 2 50 m W,全零输入时功耗为 2 0 m W,电路芯片面积为 1 .8mm× 2 .4mm.     

微机械数模转换器的原理与应用

微机械数模转换器是一种用数字信号精确控制微执行器输出量的新方法,本文介绍了微机械数模转换器的概念,分析了"C-2C梯型网络”、"逐级衰减”两种实现方案的基本原理和结构,对它们的误差、最大分辨率等特性进行了分析.最后对微机械数模转换器应用领域和下一步的发展进行了展望.     

零交越失真放大器改善DAC系统线性度

在很多应用中,数模转换器经常与放大器配合使用数模转换器广泛用于各种应用中,并常常搭配放大器使用,以便对输出信号进行调理。放大器可以提升输出电流驱动能力、将差分信号转换为单端输出信号、隔离下游信号路径,或者提供互补双极性输出电压。图1显示的是单电源供电的典型信号链,由基准电压源、数模转换器和缓冲器组成。为了保持高动态输出范围和高信噪比性能,数模转     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.