DETERMINATION OF GENERATION LIFETIME FROM C-t TRANSIENTS UNDER LINEAR VOLTAGE RAMP BIAS

When a linear voltage ramp is applied to the gate of a MOS capacitor,a capacitance-time(C-t)transient is observed.The MOS capacitor is biased into strong inversion before apply-ing the voltage ramp in order to eliminate surface generation.From C-t transient curve obtainedexperimentally the minority carrier generation lifetime in semiconductor can be determined.Theexperimental results show that for the same sample the lifetimes extracted from C-t curves un-der varying voltage sweep rates are close each other,and they are consistent with the lifetimesextracted by saturation capacitance method.     

用线性电压扫描的电容-时间瞬态测定少子产生寿命

本文建议用耗尽的线性扫描电压扫描MOS电容样品。扫描开始前MOS电容被置于强反型态,以消除表面产生的影响。根据扫描所得的电容-时间瞬态曲线,可确定样品中少于产生寿命。实验表明,对于同一个MOS电容样品,不同电压扫描率下得到的结果有很好的一致性,且与饱和电容法的结果相符合。     

Determining the generation lifetime in a MOS capacitor using linear sweep techniques

A comparison between two linear sweep techniques for generation lifetime profiling is reviewed here. These semiconductor characterization techniques find widespread application because of their availability in commercial equipment and ability to reduce the measurement time. It is shown experimentally that parameters such as generation lifetime and surface generation velocity determined by linear sweep techniques agree well with those obtained from pulsed MOS capacitor measurement.     

电场增强载流子产生中产生电流与宽度的关系

研究了深能级中心电场增强载流子产生现象，得到的产生电流与产生宽度的理论关系，能较好地与实验结果相符合。     

Theory of non-equilibrium phenomena in an MIS device under linear voltage ramp bias

A theoretical investigation into the non-equilibrium characteristics displayed by a metal-insulator-semiconductor (MIS) device when subjected to a linear voltage ramp is presented. Unlike previous theoretical analyses a time varying bulk trap generation rate is considered. It is shown that the current-voltage characteristics obtained by including this time dependence are the same as those obtained by assuming the bulk traps generate instantly at their steady-state value. Two different starting conditions are considered, namely, accumulation or depletion and strong inversion. The problem associated with commencing the sweep in accumulation or depletion when the concern is only with bulk properties is one of interface trap emission and generation and the effect these may have on the resulting I–V characteristic. This is overcome by initially biasing the device into strong inversion. For this condition bulk trap generation actually takes place right up to the semiconductor surface even though those traps near the surface have an initial occupancy of zero.     

Determination of recombination lifetime in MOS structures by a sine voltage-sweep technique

A sine-voltage technique for measurements of recombination lifetime in metal oxide semiconductor (MOS) structures is proposed. When a fast sine-voltage sweep ramp is applied to the gate of an MOS capacitor a non-equilibrium depletion layer is formed and electron–hole generation starts in the space–charge–region and in the bulk. If the measurements are performed at elevated temperature so that quasi-neutral region generation rather than space charge region generation dominates, then the diffusion length, consequently the recombination lifetime, can be determined.     

一种可用于直接计算产生寿命的产生区宽度模型

本文在分析已有的深耗尽态下半导体表面产生区宽度模型的基础上,提出了一个可用于由MOS结构的电容时间瞬态特性直接计算产生寿命的新模型。该新模型可以看作是Rabbani Rabbani模型的一种简化,但同时又可看作是对Zerbst模型的一个改进。实验数据的分析表明,用该模型得到的产生寿命值与Rabbani模型的结果基本一致。     

Generation lifetime improvement on MOS capacitor by fast neutron enhanced intrinsic gettering technique

Minority-carrier generation lifetime of MOS capacitors was improved by performing a fast neutron enhanced intrinsic gettering (NEIG) technique on the Czochralski (CZ) silicon wafers on which the devices were fabricated. With NEIG, the minority-carrier generation lifetime was possibly to be elevated high to 822 μs.It was shown that the NEIG method can be used to substitute for the conventional three-step H-L-H (H: high temperature annealing for a long time, L: low temperature annealing for a long time) intrinsic gettering method to have equivalent or better electrical properties but saving the processing time.     

非均匀掺杂衬底MOS结构少子产生寿命的测量

本文分析了非均匀掺杂衬底MOS电容对线性扫描电压的瞬态响应,提出了三角波C-V技术测量非均匀掺杂MOs电容少子产生寿命的方法.该方法简单、且不需知道衬底的掺杂分布.     

Theory of field enhanced non-equilibrium transients in MIS devices under a linear voltage sweep

A theoretical method has been formulated to simulate the field enhanced non-equilibrium transients in MIS devices under linear voltage sweep. Unlike previous theories the carrier emission probability is assumed to be field-dependent. The one dimensional Poole-Frenkel model and Hartke model are used to the carrier emission probability of traps dependent on the applied electric field. These models are quite available for coulombic centers. A reasonable model of the effective generation region is applied to analyse the transients, and the non-steady-state generation effect is taken into account. The I/V characteristics at different voltage sweep rates have been obtained. The effect of field enhanced carrier emission and the effect of non-steady-state generation on I/V characteristics are discussed in detail.     

脉冲MOS结构少子产生寿命的统一表征

本文提出了一种采用脉冲ＭＯＳ结构测量少子产生寿命的统一表征谱方法，此方法基于任何一种收敛弛豫过程均可以转换成一种衰减的指数函数的思想，应用关以样原理获得脉冲ＭＯＳ结构瞬态电容差值谱，从谱图中我们可以直接得到关于少子产生寿命信息。本文综合了众多脉冲ＭＯＳ结构测量少子产生寿命的物理模型，分析了不同模型之间的精细差别。     

风力发电对配电网电压的影响

大型风电场在接入地区配电网后,对配电网的电压有着严重的影响,主要影响因素有风场的类型、接入位置和出力大小等等。本文对风电场的无功补偿和有功功率进行了分析,并对影响配电压的因素做出了相关的阐述。     

Determination of the bulk lifetime of bare multicrystalline silicon wafers

The determination of the bulk lifetime of bare multicrystalline silicon wafers without the need of surface passivation is a desirable goal. The implementation of an in‐line carrier lifetime analysis is only of benefit if the measurements can be done on bare unprocessed wafers and if the measured effective lifetime is clearly related to the bulk lifetime of the wafer. In this work, we present a detailed experimental study demonstrating the relationship between the effective carrier lifetime of unpassivated wafers and their bulk carrier lifetime. Numerical modelling is used to describe this relationship for different surface conditions taking into account the impact of a saw damage layers with poor electronic quality. Our results show that a prediction of the bulk lifetime from measurements on bare wafers is possible. Based on these results we suggest a simple procedure to implement the analysis for in‐line inspection. Copyright © 2010 John Wiley & Sons, Ltd.     

一种新的确定少子产生特性的方法--瞬态电容弛豫谱方法

本文基于差值取样谱定理,提出一种用于同时确定少子寿命及表面产生速度的新方法———瞬态电容弛豫谱方法,该方法利用谱的峰值位置和高度能同时、准确、唯一地得到少子寿命及表面产生速度．同时将该方法与Ｚｅｒｂｓｔ方法得到的结果进行了对比．     

分布式光伏发电对配电网电压的影响及电压越限的解决方案

分布式架构下的光伏电源,带有凸显的随机特性。这种电网接入,变更了惯用的配网模式。光伏发电范畴内的精准配网模型,凸显了配网特有的多重影响。电压越限态势下的最大功率应被侧重探究。采纳电池蓄能特有的体系,化解这样的越限电压。移动平均算法,可以运算得来充放电情形下的精准功率,它缩减了输出功率、对应着的发电功率。建构仿真平台,测定得来的数值表明,储能体系对于特有的电压越限能凸显最佳的实效。     

泛洪攻击对Epidemic机制下机会网络生命期的影响

机会网络应用中存在能量无法补充的场景,泛洪是机会网络中容易发生的攻击行为。从理论上分析了在Epidemic路由机制下,泛洪攻击导致的节点能量消耗以及对网络生命期的影响。分析表明恶意节点数量的增加会对网络生命期产生显著影响,而恶意节点注入的数据分组的数量仅能在特定的场景下产生影响,且影响轻微。使用ONE仿真平台对泛洪攻击进行了仿真实验,仿真结果与理论分析的结论一致。     

Determination of the minority carrier lifetime in crystalline silicon thin‐film material

The effective minority carrier lifetimes on epitaxial silicon thin‐film material have been measured successfully using two independent microwave‐detected photoconductivity decay setups. Both measurement setups are found to be equally suited to determine the minority carrier lifetime of crystalline silicon thin‐film (cSiTF) material. The different measurement conditions to which the sample under investigation is exposed are critically analyzed by both simulations and measurements on a large number of lifetime samples. No systematic deviation between the lifetime results from different measurement setups could be observed, underlining the accuracy of the determined lifetime value. Subsequently, a method to separate the epitaxial bulk lifetime and the total recombination velocity, consisting of front surface and interface recombination between the epitaxial layer and the substrate, is presented. The method, based on different thicknesses of the epitaxial layer, is applied to all batches of this investigation. Each batch consists of samples with the same material quality but different epitaxial layer thicknesses whereas different batches differ in their material quality. In addition, the same method is also successfully applied on individual cSiTF samples. From the results, it can be concluded that the limiting factor of the effective minority carrier lifetime for the investigated solar‐grade cSiTF material is the elevated recombination velocity at the interface between epitaxial layer and the substrate compared with microelectronic‐grade material. In contrast, the samples cannot be classified into different material qualities by their epitaxial bulk lifetimes. Even on multicrystalline substrate, solar‐grade material can exhibit high epitaxial bulk lifetimes comparable to microelectronic‐grade material. Copyright © 2012 John Wiley & Sons, Ltd.     

双辅助光作用下半导体光放大器性能分析

半导体光放大器以其良好的非线性在全光网络中具有广泛应用,但较长的载流子恢复时间一直是制约其用于超快全光信号处理的速率瓶颈,基于包含自发辐射噪声的半导体光放大器模型,探讨了提高半导体光放大器增益恢复时间的有效途径,通过对制约透明波长移动,增益饱和与有效载流子寿命的相关因素进行数值分析,得出以下结论:与单辅助光相比,采用双辅助光可以在不牺牲信号增益的前提下进一步缩短载流子寿命,因而是提高半导体光放大器增益恢复时间的有效途径,这一点对工程设计和应用具有一定的指导意义.     

基于线性递减系数粒子群优化算法的组卷实现

为了避免目前常用的组卷算法组卷时间长、程序结构复杂、收敛速度慢等缺陷,提出基于线性递减系数粒子群优化算法的组卷策略。通过调整惯性系数,使得步长较小,惯性权系数的变化幅度小,这种减小趋势较为缓慢的方法能够避免陷入局部最优。并对数学模型以及线性递减惯性权系数进行了理论设计,同时通过编程实现了该算法。测试结果表明加入线性递减系数后运算迭代次数明显减少,证明加入线性递减系数后的组卷策略收敛性好,能够高效准确地按照一定的预期条件进行组卷,符合预期要求。