一种新型电荷泵电路的设计

文章提出了一种新的全差分电荷泵结构，与传统电荷泵电路相比，这个电路具有输出范围大和无跳跃现象的优点，同时还可以有效地解决电荷泄漏和充放电失配等问题。     

基于常数跨导轨到轨运算放大器的新型电荷泵

针对传统电荷泵电荷共享引起的输出电压波动、充放电电流失配引起的电路杂波问题,设计了一种新型电荷泵。该电荷泵电路采用常数跨导轨到轨运算放大器,降低了电荷共享引起的输出电压波动;采用基于全差分放大器的负反馈结构,解决了充放电电流失配的问题。基于SMIC 0.18 μm CMOS工艺,利用Cadence软件完成了电路的设计与仿真。结果表明,在0.5～1.5 V输出电压范围内,该电荷泵充放电电流失配小于2%;与传统电荷泵相比,该电荷泵输出电压的波动减小了1.5 mV,并且采用该电荷泵的锁相环输出频谱噪声减小了10 dB。     

高速运算放大器低失调输入级的设计

差分对结构是运算放大器(运放)的基础结构,对电路性能至关重要。现实中,工艺偏差无法避免,其带来的失配会影响运放的精度。对多级运放而言,输入级的失调程度决定了整个放大器的精度,因此低失调输入级成为运放设计的重点之一。为获得低失调的运放输入级,研究了差分对电阻R_C和电路失配的关系,通过修调失配电阻ΔR_C补偿其余失配项带来的影响。使用西岳4μm 50 V的工艺做全芯片参数验证,结果表明,失调电压低于60μV,相较于通用运放减小了76%;温漂系数可达0.3μV/℃,相较于通用运放减小了50%。这种方法简单、方便,可避免对电路结构做大规模调整,且对电路功耗的影响可以忽略。     

兼有高Q值、高电感值、高线性度的新型全差分有源电感

联合采用Cascode拓扑、电阻反馈网络和电流前馈技术,提出了一款兼有高Q值、高电感值、高线性度的可调谐的Cascode新型全差分有源电感。基于TSMC 0.18μm CMOS工艺,利用安捷伦公司的射频仿真工具ADS完成了有源电感的设计与仿真验证,应用Cadence Virtuoso工具完成了版图的绘制。结果表明,通过改变差分有源电感外加偏置,可以实现Q和电感值的可调,在1.2 GHz时Q值达到了最大值2 653,并且在此频率下电感值也高达15.563 n H,同时电感的线性度与没加电流前馈时相比提高了11.3 d BV。     

新型全差分电荷泵设计

采用差分输入和差分输出方案，设计了一种新型的全差分电荷泵。采用差分输出不仅能够降低电荷泄满所带来的电压噪声，而且能够提高电荷泵的上升和下降速度，从而提高锁相环的工作速度，还能增大输出电压的范围。在差分输入端，采用正反馈电路结构，以提高开启和关断速度，并降低功耗。上拉泵电路和下拉泵电路完全对称，能够消除电流失配所带来的噪声。     

用分布电容模型分析和优化差分电感

建立了预测片上等效寄生电容的片上电感分布电容模型.预测和解释了差分电感的自激振荡频率的差异.实测数据显示,与单端驱动模式下的相同对称电感相比,差分驱动模式电感提高最大品质因数127%,具有更大的工作频率范围.设计和验证了低寄生电容的差分电感.     

低失配GaAs HBT 1.5 bit高速模数转换器设计

介绍了一款基于GaAs HBT工艺的1 GS/s 1.5 bit模数转换器。通过分析模数转换器(ADC)的参考电压失配的来源,引入一种能提高电路对称性的新型差分参考网络架构,提出了减小失配的设计方法,显著提高了参考电平的对称性和一致性,从而减小参考电平的失配。此外,分析了比较器的静态和动态失配电压,对迟滞现象进行了解释。针对ADC的特点,详细分析了新型差分参考网络和比较器的关键设计参数。芯片实测结果表明,片内参考电平失配不超过1 mV,采样频率达到1 GS/s,功耗为350 mW。     

集成电感设计优化方法

分析了已有电感结构,提出了一种独特的高性能的优化方案,使得螺旋电感的品质因数和差分特性都有了显著的提高.该优化设计尤其适合高性能全差分压控振荡器对高性能螺旋电感的需要.选取典型的单层正方形螺旋电感作为测试对象,工作频率2.439 GHz,芯片面积最大值限定为250 μm×250 μm,最小线间距为5 μm.     

射频集成电路对称型螺旋电感研究

针对片上集成螺旋电感的建模,研究并设计了相关的优化方法。分析了已有电感结构,提出了一种高性能的优化方案,使螺旋电感的品质因数和差分特性都有了显著的提高,为螺旋电感设计中品质因数和电感值的折中提供更大的选择面。该优化设计尤其适合高性能全差分压控振荡器对高性能螺旋电感的需要;优化设计选取典型的单层螺旋电感作为测试对象,工作频率为2.439GHz,芯片面积最大值限定为250μm×250μm,采用ASITIC提供的默认工艺。     

采用Cascode拓扑和RC反馈网络的高Q差分有源电感

针对传统全差分有源电感在高频下品质因子Q较低的问题,联合使用Cascode拓扑和RC反馈网络对其进行优化。组合电路引入的双重负阻有效抵消了有源电感的寄生电阻,进而有效提高了高频下的Q值。基于Jazz 0.35 μm SiGe BiCMOS工艺,利用射频仿真软件ADS完成电路设计与仿真。仿真结果表明,在联合采用了Cascode拓扑和RC反馈网络后,在频率大于1 GHz时,有源电感的Q值明显提高;在1.3～3 GHz频率范围内,Q值均大于20;在2.1 GHz时,Q值达到最大值4 416,电感值变化范围为6.9～12 nH。     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.