可修调的高阶曲率补偿基准电压源

设计了一款带有误差放大器和电阻修调电路的分段曲率补偿基准电压源。通过分段电流补偿降低了温度系数;采用数字修调网络和熔丝修调网络,减小了电阻随机误差;采用误差放大器提高了电源抑制比,使基准电压精度得到显著提高。电路基于XFAB 0.35 μm高压CMOS工艺设计,仿真结果显示,在-40 ℃~125 ℃的温度范围内和多种工艺角下,当输出基准电压为3.0875 V时,温度系数为4.1×10-6/℃,低频电源抑制比达到-70 dB。该电路的性能指标大大优于同类型产品,是一款适用于汽车电子芯片的高精度电压基准源。     

一种输出可调的高精度开关电容基准电压源

设计了一种输出可调的高精度开关电容基准电压源,与现有基准电压源相比,该电路可在圆片阶段利用熔丝修调校正技术对基准电压进行修正,降低芯片制造成本。电路采用开关电容结构降低运放输入失调电压对电路的影响,具有高精度的特点。将该基准电压源应用于一款语音编解码芯片,测试结果表明,其在25℃下输出基准电压为2.355V,在-40～80℃范围内温度系数为19.46×10^-6/℃。     

一种用于模拟电路修调的EEPROM电路

介绍了一种用在模拟电路中修调的EEPROM电路.该电路采用一种新型的单层多晶EEPROM结构,与传统的双栅EEPROM结构相比,该结构与数字CMOS工艺兼容,成本低、成品率高.使用在一个基准电压电路中时,其基准电压的调节范围达到±4.82%,调节精度达到4mV.EEPROM修调电路可广泛应用于各种高精度需求的电路中.     

多管芯并行测试的熔丝修调方法探索

随着熔丝在电路设计中的应用普及,测试环节对熔丝修调的要求也越来越高,对测试人员提出了更大挑战。修调熔丝的目的是为了获得更精确的电压、频率或其他特性。为了提高测试效率,需要在多管芯并行测试的情况下,提高熔丝修调的准确性和修调速度。文章介绍了常见的熔丝特性及典型熔丝类集成电路在多管芯并行测试情况下的熔丝修调方法,并进一步研究了降低修调环节对测试系统资源的占用、提高修调效率、简化测试程序等几个方面的优化方法。     

熔丝类电路的修调探索

随着熔丝在电路设计中的应用普及,测试环节对熔丝修调的要求也越来越高,对测试人员提出了更大挑战。修调熔丝的目的是为了获得更精确的电压或者频率,按照制造材料和工艺可分为金属和多晶硅两种类型。不同的工艺结构决定了不同电路的熔丝有不同的特性,修调时需要针对具体电路具体分析,选择适宜的修调方案,并且编写简洁高效的修调程序。文章介绍了常见熔丝的特性,总结几种常用的修调熔丝方法,并分析了这些方法的各自特点,同时对修调熔丝的程序算法做了探讨。     

一种用于温补晶振的EEPROM修调电路设计

设计了一种用于温度补偿晶体振荡器(TCXO)的数字修调电可擦除只读存储器(EEPROM)电路.该电路具有正常工作模式和RAM WRITE、EEPROM WRITE、EEPROM READ三种测试模式,用于TCXO中模拟补偿电压的修调.在SMIC 0.35μm工艺下,采用HSPICE工具对设计的电路进行了仿真与验证,结果表明该电路具有可靠性高和功耗低的优点.     

适用于片内集成的可修调低失调LDO

提出了一种新型可修调低失调LDO电路,该电路适于片内集成应用.现有的修调方法一般直接作用在反馈网络中,修调电路的自身失调会造成修调精度损失.本文提出一种失调隔离模块,以大大减小修调电路引入的误差.仿真结果表明,在修调电路发生10％的电流失调时,输出电压仅变化0.31％,使LDO输出电压的修调获得很好的线性度.     

一种适用于DC/DC控制器的测试及修调电路设计

采用0.25μm BCD商用工艺,设计了一种适用于DC/DC控制器的测试及修调电路.该电路基于引脚功能复用的思路,通过对特定引脚施加特定信号,在不影响控制器正常工作时的引脚信号状态的情况下,既能够在圆片级或封装后实现内部信号的读取以及参数指标的修调,又能够克服封装寄生效应对高电压精度以及大电流测试的影响,具有测试操作简单、测试成本低廉、测试范围广泛等优点.该电路缓解了传统PAD扎针加压方案在熔丝数量较多时突出的面积问题;解决了传统激光切割方案需要昂贵激光修调设备及编写ATE程序的成本问题;改善了两种传统修调方案均只能在圆片级测试,不适合高精度、大电流测试的应用问题.该电路内部结构包括寄存器时钟及数据输入电路、测试及修调使能电路、测试及修调阵列电路、测试数据输出电路.仿真结果表明,在DC/DC控制器开环状态下,通过配置特定端口的数据位,能够通过测试电路实现振荡器输出振荡信号等内部典型信号的输出,实现关键指标导通电阻的测试,通过修调电路实现关键参数基准电压精度的修调.     

采用熔丝修调技术的高精度电流舵D/A转换器

高精度D/A转换器的实际精度往往低于理论上的精度。针对这个长期困扰的难题,在设计16位D/A转换器的过程中,提出了一种熔丝修调技术,即通过修调电流源输出端的电流,有效地减小电流源失配和有限输出阻抗对D/A转换器的DNL和INL的影响,大幅度提高D/A转换器的精度。基于0.18 μm CMOS 工艺的测试结果表明:在采用熔丝修调技术前,该电路的DNL和INL分别为－0.72~9.07 LSB和－5.55~18.1 LSB;在采用熔丝修调技术后,该电路的DNL和INL分别为－3.95~0.70 LSB和1.94~8.06 LSB。当输入信号频率为102 MHz、采样频率为500 MHz时,SFDR达到82.16 dBc,完全满足D/A转换器高精度的要求。     

一种应用于反熔丝FPGA的电荷泵电路

电荷泵（Charge Pump）电路以其可成倍输出自身输入电压的特性而被广泛应用于各种芯片的驱动电路中。在反熔丝FPGA中,反熔丝为高压一次编程器件,在编程过程中需要通过高压隔离管将反熔丝与其它器件隔离开,而高压隔离管在工作时需要大于芯片电源VCCA的电压来驱动,如何提供高压保证隔离管能够无损传输数据是反熔丝FPGA研发时必须要考虑的问题。本文提出了一种应用于反熔丝FPGA的电荷泵电路,电路具有快速启动的特点,同时电路工作频率可调,通过在电路中增加冗余NMOS结构,提高了电路在工作中的安全性,该电路在工作时能保证熔丝编程过程中除了反熔丝以外的其他器件不受编程电压的影响,且在编程结束后通过电荷泵输出电压打开隔离管完成信号的无损传输,能够满足反熔丝FPGA对于电荷泵的需求。     

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.