0.18-μm SOI/CMOS工艺下无基准源的10位50MS/s低功耗逐次逼近型模数转换器

本文介绍了一个10位50MS/s无需基准源的低功耗逐次逼近型模数转换器。设计中采用了一种高能效的开关方案。该开关方案使得模数转换器无需额外的模拟电压或者片上/片外基准电压源就能获得低功耗以及良好的高速操作性能。设计中利用片上校准数模转换器来对Latch型的灵敏放大器进行校准,消除失调电压并且去除对前置放大器的依赖性。该设计利用IBM 0.18-μm 1P4M SOI/CMOS工艺实现。该逐次逼近型模数转换器在1.5V电源电压,5MHz的输入频率以及50MS/s采样速率条件下,能够获得56.76 dB SNDR,此时功耗为1.72 mW, 从而取得FOM值为61.1 fJ/conversion-step。     

一个具有改进开关逻辑的12位1MHz采样速率的低功耗逐次逼近型模数转换器

作为数据采集系统中的关键模块,逐次逼近型模数转换器的功耗决定了整个系统的功耗水平。本文给出了一个具有改进开关逻辑的12位1MHz采样速率的低功耗逐次逼近型模数转换器。通过采用所提出的开关逻辑,该逐次逼近型模数转换器的功耗和面积跟采用传统开关逻辑的逐次逼近型模数转换器相比都会有很大的降低,其中开关逻辑的平均功耗大约降低了80%,总的电容面积减小50%。不仅如此,文章还提出了一种简化的数字控制逻辑来降低数字控制电路的功耗和面积。仿真结果表明和传统的数字控制逻辑电路相比,提出的简化数字逻辑的功耗可以减小大约50%。所设计的芯片在标准的0.35微米的CMOS工艺下进行了流片,芯片内核的面积为1.12平方毫米。在-55℃到150℃温度变化范围下,芯片100KHz的输入信号可以测得64.2dB的SNDR。在给定3.3V的电源电压下,芯片的功耗仅为0.72mW。     

高性能带隙基准源的分析与设计

全面分析了CMOS带隙基准的主要非理想因素,给出了相应的补偿方法,并以此为基础设计了一种高精度的带隙基准源电路。该电路在SMIC 0.35μm CMOS工艺条件下的后仿真结果表明,基准输出电压的温度系数为3.4 ppm/℃(-40~ 125℃),电源抑制比为85 dB。此带隙基准源已应用于14位D/A转换器芯片中,并参加了MPW流片,该D/A转换芯片已经通过测试。     

用于SAR ADC的低开销电容开关时序设计

逐次逼近型模数转换器(SAR ADC)中,数模转换器单元(DAC)是能耗和面积的主要来源之一。为了降低DAC的能耗和面积,提出了一种低开销电容开关时序,以此设计了DAC的结构,并进行逻辑实现。相比于传统型开关时序,该电容开关时序使得DAC的能耗降低了98.45%,面积减小了87.5%。基于该电容开关时序实现了一种12位SAR ADC。仿真结果表明,在1.2 V电源电压、100 kS/s采样速率的条件下,该ADC功耗为12.5 μW,有效位数为11.2位,无杂散动态范围为75.6 dB。     

一种低压新型曲率补偿基准电压源设计

基于Chrt0.35 μmCMOS工艺,设计了一种基于亚阈值工作区的一阶温度补偿和I²_PTAT电路组成的带隙基准电压源。芯片测试结果表明,电路在1.2 V电源电压下便可工作;在温度-20~120 ℃范围内,基准电压源平均温度系数＜2×10^-6/℃。该带隙基准源具有良好的可应用于高精度模数转换器(ADC)、数模转换器(DAC)和系统集成芯片(SOC)中。     

一种用于音频Σ-ΔA/D转换器的CMOS带隙电压基准源

在传统带隙基准电压源电路结构的基础上,通过在运放中引入增益提高级,实现了一种用于音频Σ-ΔA/D转换器的CMOS带隙电压基准源。在一阶温度补偿下实现了较高的电源抑制比(PSRR)和较低的温度系数。该电路采用SIMC 0.18-μm CMOS工艺实现。利用Cadence/Spectre仿真器进行仿真,结果表明,在1.8 V电源电压下,-40～125℃范围内,温度系数为9.699 ppm/℃;在27℃下,10 Hz时电源抑制比为90.2 dB,20 kHz时为74.97 dB。     

一种具有失配校准技术的轨到轨输入逐次逼近型模数转换器设计

传统的逐次逼近型模数转换器很难对输入等于电源电压的模拟信号进行正确的模数转换,本文提出了一种新型的逐次逼近型模数转换器,能够对输入幅度等于电源电压的输入信号进行正确的转换,并且具有用于缩短采样时间的采样保持放大器电路,同时针对比较器失调和电容阵列失配提出了校准技术,进一步提高了转换精度。测量结果显示该模数转换器的最大信噪谐波失真比可以达到72dB,有效输入信号带宽为1.25MHz,消耗功耗为1mW,相应的FOM指数为123fJ。     

一种用于生物医学信号的自适应SAR ADC

基于0.18 μm CMOS工艺,设计了一种用于生物医学信号的12位逐次逼近型模数转换器(SAR ADC)。数模转换器采用分段结构电容阵列,并加入1位冗余位。比较器采用互补输入对管构成的动态比较器,以减小噪声和功耗。栅压自举开关被用于采样保持电路,并增加了堆叠管和虚拟管。针对生物医学信号具有稀疏性的特点,通过延时上极板复位时间的方法检测两次采样电压差值,实现采样率自适应切换。仿真结果表明,在120 kS/s采样率、1 V电源电压的条件下,该SAR ADC的功耗仅为4.65 μW,无杂散动态范围为76.29 dB,优值为16.9 fJ/(conv·step),有效位数达11.16 bit。     

宽温范围高温度稳定性曲率互补电压基准设计

针对当前射频系统中电源管理芯片在宽温度范围下对带隙基准稳定性的较高要求,提出了一种新型互补带隙基准电路结构,通过将带隙基准与MOS弱反型区基准的温度系数曲率互补叠加,实现了极宽温度范围内带隙电压基准的高温度稳定性输出.采用0.35 μm CMOS工艺对所设计的电路进行了流片验证,测试结果表明,基准电压源工作电压为5V时,输出基准电压1.28 V,在-55 ～125℃温度范围内,温度系数可达4.5×10-6/℃,频率1 kHz时,电源抑制比(PSRR)可达-60 dB,100 kHz时,PSRR可达-55 dB,电压基准源芯片面积为0.22 mm×0.15 mm.     

一种12位1 MS/s数字自校准SAR ADC

设计了一种12位1 MS/s单端结构的自校准逐次逼近型模数转换器(SAR ADC)。采用串联三段式7位校准DAC阵列结构来校准高6位误差电压,减小了面积,扩大了校准范围。将校准DAC的初始态接为中间态,简化了校准逻辑控制过程。采用“双寄存器”预判的方式,提高了回补校准码的效率。在电源电压为3.3 V、转换速率为1 MS/s的条件下,进行了仿真验证。结果表明,该SAR ADC校准后,SNDR从校准前的49.2 dB提升到71 dB,DNL、INL分别从校准前的-1 LSB /+21.250 LSB、-17.398 LSB /+10.152 LSB减小到-0.25 LSB /+0.5 LSB、-1.048 LSB /+0.792 LSB。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

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.