碲镉汞长波探测器暗电流优化模拟

报道了利用Silvaco软件对Hg1-x Cd x Te(x=0.22)n-on-p型长波探测器的模拟仿真结果。采用二维简化pn结模型,以品质因子R0A为标准,模拟计算了载流子寿命、缺陷密度、表面态、p区受主浓度、p区厚度、n区厚度宽度对暗电流的影响,得出在良好的品质因子范围内各个参量可以接受的范围。并针对重要参量利用软件对其复合速率,电流分布,载流子浓度等进行了详细模拟分析,为探测器设计制备提供了参考。     

瞬态光响应法测试中波碲镉汞器件少子寿命的新方法

在测试中波碲镉汞光伏器件的瞬态响应时,当激光光斑照射器件表面位置距离光敏面较远时,器件表现为特殊的双峰脉冲响应现象,分析表明出现这种异常双脉冲现象的原因是光敏区内的少子漂移和光敏区外侧向收集的少子扩散有时间上的差异。通过对器件施加反向偏压,脉冲响应随反向偏压的增大由双峰变成单峰的实验结果,验证了少子侧向收集是导致器件形成双峰的主要原因。对第二个峰拟合得到p区的少数载流子寿命。将瞬态响应获得的少子寿命与该p型中波碲镉汞材料的理论计算和光电导衰退法得到的少子寿命相对比,发现三种方式得到的少子寿命随温度的变化趋势基本一致,这说明了可以通过瞬态光响应得到中波碲镉汞器件的少子寿命。     

快速软恢复SiGe功率开关二极管的结构设计与特性分析

为了进一步提高SiGe/Si异质结功率开关二极管的性能,提出了一种SiGe功率开关二极管的新结构,用交替的p 、n 区形成的mosaic结构来代替原常规的n 区,关断时可同时为电子和空穴的抽取提供通道使阴极具有理想欧姆接触.该结构可大大提高开关速度,并获得很软的反向恢复特性及很低的漏电流.与常规p (SiGe)-n--n 功率开关二极管相比,反向恢复时间缩短了近2/3,反向峰值电流降低了约1/2,漏电流降低了约1个数量级.另外,嵌镶结构中p 区的厚度对器件性能有很大影响,调整p 区的厚度可实现器件的反向耐压能力和反向恢复特性之间很好的折衷.这种性能的改进无需采用少子寿命控制技术因而很容易集成于功率IC中.     

重掺杂P型Si1-xGex层中少数载流子浓度的低温特性

考虑了重掺杂引起的禁带变窄效应,建立起少数载流子室温和低温模型,并进行了定量的计算。研究发现,p-Si1-xGex中的少子浓度(电子)随x的增加而增加。在重掺杂条件下,常温时,少子浓度随杂质浓度的上升而下降;而低温时,少子浓度却随杂质浓度的上升而上升。     

脉冲恢复技术测量有限宽基区HgCdTe光电二极管少子寿命

利用脉冲恢复技术测量了有限宽基区n+-on-p光电二极管中的少子寿命.实验发现,反向恢复时间同正、反向电流的大小有关.从恢复时间ts与IF/IR函数关系提取的少子寿命随着基区厚度与少子扩散长度比值降低而明显增大.在77 K时,采用传统方法脉冲回复技术提取的少子寿命为28 ns,而当考虑短基区效应时,所提取的少子寿命为51 ns.这表明HgCdTe光电二极管的基区厚度与少子扩散长度比值是采用脉冲恢复技术测量少子寿命技术中的一个重要参数.只有当基区厚度大于三倍少子扩散长度时,传统方法中无限基区厚度的假设条件才成立.     

PCB镀通孔疲劳寿命对设计参数的灵敏度分析

在PCB镀通孔疲劳寿命评估IPC模型的改进模型基础上,分析了镀通孔疲劳寿命对基板厚度与孔径之比(即厚径比l/r0)、基板厚度与镀层厚度之比(l/t)以及基板作用半径与孔半径之比(R/r0)的灵敏度。结果表明,镀通孔疲劳寿命对(l/r0)的灵敏度随(l/t)增大而减小;对(l/t)的灵敏度随(l/r0)增大而减小;而对(R/r0)的灵敏度则随(l/r0)增大而增大、随(l/t)增大而减小。最后,利用IPC的试验研究结果数据进行了验证。     

条形半导体激光器中电过程和光波导过程的精确理论

提出条形半导体激光器中稳态电过程和光波导过程及其相互作用的精确模型,并从电极电压算起得出阈值以上的电压电流分布和基模光场分布的相互影响和变化的计算机结果.指出简单的p-n结注入公式和任何固定形式的结电流分布假设对分析条形半导体激光器中的电过程和光波导过程都不适用,本文还探讨了光功率-注入电流特性出现扭折的机制和条件.     

GaP∶N 绿色 LED n2层载流子浓度的优化

在已报道的p-n2-n1结的势垒分布计算的基础上,对该结构的浓度分布进行了计算.对于正偏情形,计入了n2区产生的压降.考虑到GaP∶N LED发光区主要在p区,注入效率γ=jn/(jn+jp),jn和jp分别为电子电流和空穴电流.p区内的少子扩散可视为向无限远处的一维扩散;n2区内外加正向偏压时电场不能忽略,空穴又被n2-n1 结势垒阻挡(设被完全阻挡),则问题归结为求解有限厚度层中空穴的扩散和复合方程, 由边界条件求出空穴扩散电流.将求出的电子扩散电流和空穴扩散电流代入注入效率的表达式即可求得γ.对在合理的参数值范围内的计算结果进行了讨论.分析表明:当n2值在1015～1016cm-3范围内时,注入效率较高,与实验结果基本相符.     

变磁场I-V法对碲镉汞光伏器件少子扩散特性的研究

零偏压电阻-面积乘积(R0A)和反向饱和电流密度J0是决定光电二极管性能的重要参数．提出了一种对碲镉汞(Hg1-xCdxTe)光伏器件的少子扩散特性进行研究的有效方法．利用变磁场下的电流-电压(I-V)测试,得到了组分x在0．5与0．6之间的器件R0A和J0随磁场强度B变化的函数关系．由实验结果估算得到了室温工作的短波红外(SWIR)碲镉汞光伏器件的少子扩散长度．其数值与用激光诱导电流(LBIC)方法得到的相一致．     

环孔p-n结理论分析

在对环孔p-n结作近似假设的基础上，忽略了产生－复合电流、隧穿电流和表面复合电流的影响，假设在低温下扩散电流起主要作用，并认为电极与结区之间的接触为欧姆接触，建立了环孔p-n结的电流模型。根据此模型得出了环孔p-n结的电流密度方程和ROA的计算表达式，由于n区空穴的电流密度相对p区要小得多，在简化的表达式中忽略了n区电流密度的影响。最后对上述结果进行了数值分析和计算，分别做出了RoA在中波和长波波段随温度和截止波长变化曲线。从曲线可以得出：当截止波长在中波波段3－5μm时，77－150K的温度范围都可以使用，但只有在130K或更低的温度下才有较好的性能。目前在中波段的R0A值已经达到10^9Ωcm^2，比理论值要低2－3个数量级；对于8－10．4μm波段，120K以下都有性能，而10－14μm波段，要工作在100K温度之下。     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

A Versatile Mixed-Signal Pin Approach for Cost-Effective Test of Automotive ICs

Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.     

Optical vibration and deviation measurement of rotating machine parts

It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer （LDV）.     

INTEGRATION OF OPTICAL AND WIRELESS NETWORKS

正For a long time,optical and wireless systems/net-works are developed in separate communities witha few attempts for in-depth convergence.In fact,it prom-ises many advantages to combine the optical and wire-less technologies in the levels of systems and networks.Recently,both academia and industry have made manyefforts to enter a new phase of development to take op-tical and wireless systems as fully integrated networks.To provide high bandwidth and reliable service for bothfixed and mobile users,a well-designed network must     

社长序言（英文）

正Happy New Year!As we step into a new year,we take a look back at the key feature topics covered in China Communications over the past 12 months and set out our expecta-     

云计算专题（英文）

正Cloud computing is a novel computing paradigm that utilizes remote cloud resources to achieve a high-performance computation.Cloud provides infrastructure,platform and software as different on-demand services.China has made remarkable progress in cloudbased products and operating system technology.The government,enterprises and research institutions are all active in the development of cloud computing-related projects.Despite the progress,many important problems     

Call for Papers—Feature Topic,Vol.12,No.3,2015

正Smart Grid Communications The electric power industry is undergoing profound changes as the industry aims to capture the promise of a smart grid for a sustainable energy future.Enabled by the advanced sensing devices such as Phasor Measurement Units(PMUs),increasingly powerful