硅片方块电阻计量标准装置研制

对测量方块电阻的双配置四探针法进行了研究,从理论上分析了该方法的优点：测量结果与探针间距无关,可使用不等间距探针头,具有自动修正边界影响的功能,不必寻找修正因子,论述了RS大小样片及边界附近的测试原理,给出了RS的计算公式。研制了基于双配置四探针法的硅片方块电阻计量标准装置,论述了该装置的软硬件设计,为校准硅片方块电阻标准样片提供了技术手段。解决了硅片方块电阻参数的量值传递问题。     

无功补偿不及时对母线不平衡电量值超标的影响

0引言 通常,变电所一般都要进行母线不平衡电量值计算,母线电量是否平衡主要反映电量供给有无漏计、少计、错计等.造成母线不平衡电量值超标的原因很多,但比较常见的原因有如下4种:①电能表的校验准确度;②二次接线是否正确、有无断线;③电缆是否完好;④互感器准确度及其二次保险有无熔断等.另外还有一个比较特殊的原因是无功补偿不及时,但由于这种情况发生的几率较少,并且比较隐蔽,一般易被忽略,造成现场检查工作费时费力.现以笔者在现场发现的一起事例对其进行分析.     

Impact of high-k spacer on device performance of a junctionless transistor

The impact of spacer dielectric on both sides of gate oxide on the device performance of a symmetric double-gate junctionless transistor (DGJLT) is reported for the first time. The digital and analog performance parameters of the device considered in this study are drain current (I _D ), ON-state to OFF-state current ratio (I _ON /I _OFF ), subthreshold slope (SS), drain induced barrier lowering (DIBL), intrinsic gain (G _m R _O ), output conductance (G _D ), transconductance/drain current ratio (G _m /I _D ) and unity gain cut-off frequency (f _T ). The effects of varying the spacer dielectric constant (k _sp ) on the electrical characteristics of the device are studied. It is observed that the use of a high-k dielectric as a spacer brings an improvement in the OFF-state current by more than one order of magnitude thereby making the device more scalable. However, the ON-state current is only marginally affected by increasing dielectric constant of spacer. The effects of spacer width (W _sp ) on device performance are also studied. ON-state current marginally decreases with spacer width.     

纳米磷酸铁锂合成研究进展

橄榄石型LiFePO4作为新一代锂离子电池正极材料,具有比容量高、成本低、热稳定性好、环境友好等优点,拥有广阔的应用前景,但其低电导率的缺点使其商业化应用受到限制.通过合成纳米LiFePO4进而改善其电化学性能成为当前的研究热点之一.介绍了近年来国内外湿化学法合成纳米LiFePO4的研究进展,分析了不同湿化学法的基本原理、前驱物、溶剂、重要工艺条件等.比较了不同工艺路线对LiFePO4结构和形貌的影响,探讨了合成纳米LiFePO4所进行的研究工作,并指出了存在的问题.最后对纳米LiFePO4的产业化状况及发展趋势进行了展望.     

Impact of Auger recombination parameterisations on predicting silicon wafer solar cell performance

For high-efficiency silicon wafer solar cells, Auger recombination is becoming one of the most important efficiency limiting factors. For this purpose it is desirable to be able to use different Auger recombination parameterisations in advanced computer simulations. In this paper we present a method to implement arbitrary Auger parameterisations in the software package Sentaurus TCAD, enabling two- and three-dimensional simulation of solar cells using different Auger parameterisations. As examples, we implemented and investigated three different Auger parameterisations (proposed by Altermatt et al., by Kerr and Cuevas, and by Richter et al.) from the literature. For verification, we simulate Auger lifetimes for different doping densities and injection levels in crystalline silicon. The simulated Auger lifetimes are found to agree well with analytical solutions (differences less than 0.001 %). We then employ the three different Auger parameterisations for fitting measured effective lifetime curves of both \(n\) -type and \(p\) -type float-zone silicon lifetime samples and show which models are applicable under which conditions. We further compare the difference between the three Auger parameterisations by simulating characteristics of a screen-printed aluminium local back surface field silicon wafer solar cell. The simulation results agree well with the characterisation results. We find that the choice of Auger parameterisation can lead to significant differences in the predicted solar cell behaviour under one-Sun illumination. We demonstrate that different Auger parameterisations may result in significant differences in the blue response, by simulating a heavily doped emitter of an aluminium local back surface field silicon wafer solar cell.     

晶体硅太阳电池内阻对其输出特性的影响分析

从太阳能电池输出特性方程出发,经由理论作图(U-I曲线)分析晶体硅太阳电池内阻对其输出特性的影响,通过数值计算,说明当晶体硅太阳电池的并联内阻大于100Ω时可以忽略。在此基础上,得到电池串联内阻与输出电流、电压之间的函数表达式,只要实测出某一确定光照强度及温度下负载的任意一组电流、电压值,计算相应的串联内阻值,进一步计算最大功率点处的电流、电压及负载值,可为最终的最大输出功率跟踪提供一种简便方法。     

Cell adhesion characteristics of chemically modified silicon nitride surfaces

We investigated the fundamental characteristics of cell adhesion during cell culture on the Si₃N₄ surface for using it as the gate insulator in field‐effect devices. The culture medium and the surface condition of Si₃N₄ were controlled for cell culture on the Si₃N₄ substrate. When we measure electrical characteristics of cell adhesion and cell function using field‐effect devices, we require a stable measurement of the electrical signals. The serum in the culture medium includes a number of proteins, which cause instability of the potential behavior. In this paper, we show that the cell‐adhesive molecules on the Si₃N₄ surface used as a gate insulator should be designed and controlled when cell culture is performed in the culture medium without the serum. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

列尾装置用三元锂电池特性研究

根据电池实际使用要求,对列尾装置用三元锂电池进行了一系列实验。基于实验结果对电池的充电特性和在不同放电温度下的放电特性进行了详细研究和分析,对电池的使用提出了建议。实验表明:温度对电池的放电容量有影响,低温会使电池的放电容量减少,但仍远高于电池出厂要求,电池充放电特性优良。     

波浪能转换装置中双浮子特性的数值研究

本文提出了以船形大浮子和陀螺形小浮子组合的双浮子波浪能发电试验平台,并针对陀螺形浮子展开了仿真研究。通过改变陀螺浮子的锥顶半径尺寸,建立了陀螺形浮子在波浪水平和竖直冲击作用下的受力和变形模型,分析了其对波浪的适应特性、功率特性以及效率特性,并对影响浮子受力和变形的关键参量进行了优化分析。仿真结果表明,陀螺形浮子作为漂浮式试验平台的波浪能捕获装置是合理的。     

Deterioration of device characteristics of MFSFET due to fatigue

Abstract

Change of device characteristics of the metal-ferroelectric-semiconductor FET (MFSFET) with the progress of fatigue of the ferroelectric thin film are simulated in this study. The field-dependent polarization model and the square-law FET model are employed in our simulation. C-V_G curves exhibit the accumulation, the depletion and inversion regions clearly. They also exhibit the memory window of 2V. I_D-V_D curves are composed of the triode and the saturation regions. The difference of saturation drain currents of the MFSFET device at the dual threshold voltages in I_D-V_D curve is 6mA/cm², which decreases as much as 50% after fatigue. Our model is expected to be very useful in the estimation of the behaviour of MFSFET devices with the progress of fatigue.     

限幅环节对DFIG故障中输出特性的影响研究

研究了不同严重程度的三相对称故障下,限幅环节对双馈感应电机(DFIG)输出特性的影响。仿真获得不触发Crowbar动作的不同故障下,DFIG故障中稳态有功输出与稳态电压的关系;给出DFIG功率控制模块中有功功率限幅和转子电流限幅的数学模型,仿真分析了限幅环节对故障期间Crowbar动作次数、暂态有功及无功输出特性的影响。通过理论推导结果与仿真的对比,表明了故障中稳态有功输出特性由有功限幅、转子电流限幅及额定有功输出限制决定,且在严重程度不同的故障下,DFIG故障中功率输出由不同限幅环节决定。     

Measurement of the magnetic characteristics of oriented silicon steel in an arbitrary direction

The measurement method and the experimental results on the magnetic characteristics of oriented silicon steel in any direction are described in this paper. A single sheet tester of rotational loss has been used in order to simulate conditions existing in real devices. The flux of any direction is induced in the specimen by exciting from X and Y directions in the same phase. The flux density was measured by each search coil. The magnetizing force was measured by the double H-coil method. The outputs of the B-coils and the H-coils were treated by sending the outputs from the wave digitizer to the personal computer. The components of the magnetic characteristics in the X and Y directions for small values of B are the same. Only the saturation value changes, and it depends on the direction of flux.     

单向塑料土工格栅与土界面作用特性的试验研究

土工格栅与土的界面特性直接决定加筋土工程的稳定性,所以格栅与填料的界面技术指标是土工加筋关键的设计指标。本文中,以单向塑料土工格栅为加筋材料,以粘土、砂质粉土、粉细砂、砂砾料为填料,也在大尺寸接触面试验仪上进行拉拔试验;以单向塑料土工格栅为加筋材料,以粘土为填料进行直剪试验。结果表明:粘土与格栅间界面的剪切强度一般很低;砂砾料中的拉拔曲线呈台阶状,摩擦角不是常数;拉拔强度指标和直剪强度指标的适用情况不同。这些可以作为土工格栅加筋工程设计的参考。     

基于有限元分析方法对接地装置冲击特性研究

由于冲击电流的作用,接地体周围的土壤将会产生火花效应,使得土壤的电阻率会发生变化,进而对冲击电流的散流过程造成影响.因此本文采用有限元分析方法,利用COMSOL Multiphysics软件,构建了考虑火花效应的接地装置冲击散流模型,主要研究了垂直、水平接地体的冲击散流过程,通过模型的计算发现,接地装置在冲击散流的过程中电流主要从接地装置的末端散流到土壤中,这一情况也与实际情况相符合.     

Electrical characteristics of aluminum-zirconium oxide-barium magnesium fluoride-p silicon MIS capacitors

The Barium Magnesium Fluoride films have been deposited on p-Si wafers at a temperature in the range of 400-450°C in an ion assisted deposition system. X-ray diffraction analysis shows that the films are polycrystalline in nature. The BMF films were encapsulated with an electron beam evaporated Zro2 film of thickness 300°A. The capacitance-voltage (C-V) charactersitics of Aluminum-ZrO2-BMF-p Si MIS capacitors show hysteresis and the direction of the hysterisis correponds to ferroelectric polarization in the BMF film. The shift in threshold voltage was found to depend on bias voltage, ramp rate as well as measurement temperature.     

The effects of PECVD silicon dioxide passivation on the electrical characteristics of Sol-Gel deposited PZT film capacitors

Abstract

Plasma-enhanced chemical vapor deposition (PECVD) of doped and undoped silicon dioxide layers is widely used throughout the semiconductor industry for the passivation of processed devices before the final metallization processing steps. However, a reduction in the remanent polarization of PZT platinum-electrode capacitors has been observed when the capacitors were passivated with PECVD silicon dioxide films. This paper presents the results of a study to determine the effects of a standard PECVD silicon dioxide process on the retained polarization of Sol-Gel derived PZT capacitors with platinum electrodes. The retained polarization of the capacitors was measured before and after the silicon dioxide depositions. Measurements indicate that for PZT capacitors with temperature-stabilized top electrodes, there is relatively little change in the retained polarization after the depositions. However, for the PZT capacitors without the temperature-stabilized top electrodes, reductions in excess of 70% in the retained polarization can occur.     

双馈风电机组低压穿越特性对电力系统暂态稳定的影响

双馈风电机组(DFIG)的低压穿越(LVRT)特性与同步发电机不同,使得大规模DFIG接入电力系统后同步发电机的功角特性发生改变,因此分析系统暂态稳定性时有必要考虑DFIG LVRT行为的特殊性。推导机电暂态时间尺度下DFIG撬棒未投入和投入2种工况下的等值模型,基于该模型对典型LVRT策略下DFIG的外特性进行分析;基于等面积定则研究DFIG LVRT策略中无功补偿系数与撬棒电阻对电力系统暂态稳定的影响。时域仿真结果表明,提高无功补偿系数和增加撬棒电阻有利于电力系统的暂态稳定性,验证了理论分析的正确性。     

高镍-硅碳体系锂电池阻抗特性研究

高镍-硅碳体系电池是进一步提高电池能量密度的重要研究方向.为了考察负极中不同硅含量电池的循环性能,辨识电极脱嵌锂过程中的主要物理化学过程,采用电化学交流阻抗频谱(EIS)和弛豫时间分布(DRT)来研究高镍-硅碳体系电池循环前后的阻抗特性,研究发现在荷电状态(SOC)为50％时,电解液中锂离子扩散过程是电池阻抗的主要来源...