一种基于电流阶梯波的相变存储器擦驱动电路

基于相变存储器的擦操作(SET)特性,设计了一种能够产生电流阶梯波的相变存储器擦驱动电路,采用130 nm标准CMOS工艺将其与128 kb的相变存储器实验芯片集成.相比传统的单一电流脉冲擦驱动电路,这种改进后的擦驱动电路能将相变存储单元的电阻均值从15 kΩ左右降至7 kΩ左右,并且存储阵列的阻值分布一致性也得到提升...     

相变存储器驱动电路的设计与实现

介绍了一种新型的相变存储器驱动电路的基本原理,设计了一种依靠电流驱动的驱动电路,整体电路由带隙基准电压源电路、偏置电流产生电路、电流镜电路及控制电路组成.该结构用于16Kb以及1 Mb容量的相变存储器芯片的设计,并采用中芯国际集成电路制造(上海)有限公司的0.18μm标准CMOS工艺实现.该驱动电路通过Hspice仿真,表明带隙基准电压、偏置电流均具有较高的精度,取得了良好的仿真结果,在16 Kb相变存储器芯片测试中,进一步验证了以上仿真结果.     

一种高精度CMOS带隙基准电压源设计

介绍了带隙基准电压源的基本原理,设计了一种高精度带隙基准电压源电路.该电路采用中芯国际半导体制造公司0.18 μm CMOS工艺.Hspice仿真表明,基准输出电压在温度为-10～120 ℃时,温度系数为6.3×10-6/℃,在电源电压为3.0～3.6 V内,电源抑制比为69 dB.该电压基准在相变存储器芯片电路中,用于运放偏置和读出/写驱动电路中所需的高精度电流源电路.     

一种1kb相变存储芯片的设计

以中科院上海微系统与信息技术研究所自主研发的相变存储器工艺为基础,开发了一款容量为1 kb、可应用于射频标签(RFID)的嵌入式相变存储芯片.该芯片以1T1R为基本单元结构,采用箝位读出方式以及电流镜式写驱动电路,成功实现了相变存储器的读写功能.测试结果显示,该芯片可重复擦写次数达到107次,在80℃条件下数据保持力达...     

一种适用于相变存储器的低噪声时钟发生器

基于相变存储器的特性,设计了一种具有低功耗、低噪声的时钟发生器.该时钟由压控振荡器产生,并通过时钟控制电路转换为相变存储器存储操作所需的reset、set信号.由于纳米尺寸下的相变存储器件受噪声影响严重,该电路降低了外围驱动对相变存储单元的低频噪声干扰,能够改进相变存储器性能.电路采用40 nm CMOS工艺设计,电源电压为1.8V,功耗为1.26 mW,RMS抖动为0.83 ps,p-p抖动为5.14 ps,芯片面积为80 μm×90 μm.     

用于相变存储器的自适应1.5X/2X/3X高效电荷泵

针对相变存储器中编程驱动电路的电源效率问题,设计了一种1.5X/2X/3X自适应高效电荷泵,电路采用跳周期模式稳定输出电压.在中芯国际0.18 μm标准CMOS工艺模型下,对电路进行了仿真.结果表明,在输入电压为2.2～4.8 V时,输出5V电压,最大负载电流为10mA,电源效率最高可达94％.     

用于相变存储器的高效开关电容电荷泵

提出一种应用于相变存储器芯片的新型开关电容电荷泵。对于16 位的相变存储器芯片,系统擦写时间大于100 ns,电荷泵的驱动能力至少为60 mA。相比于传统开关电容电荷泵,该电荷泵根据负载电流大小自动生成一个使能信号,该信号通过控制升压模块功率管的开启与关断来调节输出电压,最终将输出电压控制在一个允许的范围内波动。采用40 nm CMOS工艺对电荷泵进行设计和仿真,结果表明在5 mA负载时,电源效率为87%,输出纹波为2.84 mV;负载电流从0 mA变化到60 mA时,电源效率皆高于82%;负载电流变化在300 mA/μs时,输出瞬态响应时间为1.63 μs,满足相变存储器芯片的使用要求。     

红外焦平面读出电路片上驱动电路设计

线列红外焦平面读出电路在正常工作时需要提供多路数字脉冲和多路直流偏置电压。本文基于0.5 μm CMOS工艺设计了一款驱动电路芯片,为电容负反馈放大型（CTIA）读出电路（ROIC）提供驱动信号。电路芯片采用带隙基准电路产生低噪声低温漂的直流偏置电压,采用数字逻辑电路生成CLK1,CLK2,RESET等八路数字脉冲。仿真及测试结果表明：驱动电路芯片输出的数字脉冲及偏置电压符合设计值,可驱动CTIA型线列红外焦平面读出电路稳定工作。     

一种适用于相变存储器锁相环时钟的新型电荷泵

设计了一款低噪声、低功耗的电荷泵,适用于相变存储器驱动电路中的锁相环时钟。与其它结构的电荷泵相比较,此款电路对时钟馈通与电荷注入等干扰免疫力强。根据相变存储器对驱动电路低噪声的性能要求,本电路具有低的热噪声和1/f噪声。仿真结果表明输出电压在0℃~80℃温度范围内最大仅有11mV的偏差,其与PFD所产生的相位噪声在1MHz频率下为-102dB。电路采用40nm CMOS工艺设计,电源电压2.5V,功耗0.125mW,芯片面积60 m×55 m。     

中小屏幕TFT-LCD驱动芯片的输出缓冲电路

在分析中小屏幕TFT-LCD驱动芯片的负荷特性的基础上,提出了一种新型的驱动电压输出缓冲电路结构.通过负反馈动态控制输出级的工作状态,具有交替提供拉电流和灌电流的驱动能力,可有效抑制输出电压的波动.与传统的两级运算放大器电路相比,该电路结构简单,稳定性能好,降低了静态功耗并节省了芯片面积.采用0.25μm CMOS工艺设计并实现了两种不同输出电压的缓冲电路.HSPICE仿真结果表明,输出电压缓冲电路的静态电流为3μA,Offset电压小于±2mV.同时,当TFT-LCD的驱动电压在-8～ 16V之间切换时,输出电压的波动范围小于±0.4V,输出电压的恢复时间小于7μs.经对工程样片的测试知,其性能完全满足中小屏幕TFT-LCD驱动控制芯片的要求.     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.