H型栅NMOS器件Kink效应的研究

H型栅NMOS器件因其强抗辐照和低功耗等优势已逐渐成为PDSOI电路设计中的核心器件。但H型栅NMOS器件的Ids-Vds曲线会在漏极电压较高时发生明显的翘曲现象,称为Kink效应。该效应严重影响一定工作条件下的电路性能和稳定性。为此,依据实测和TCAD仿真数据,分析了H型栅NMOS器件发生Kink效应的机理,并且基于0.15μm SOI工艺,进一步量化分析了顶层硅膜厚度、阱浓度、栅尺寸、温度以及总剂量辐照等方面对Kink效应的影响。最终结果表明,高漏极电压下NMOS器件体区积累大量空穴导致寄生NPN三极管开启,从而引发了Kink效应。本工作完善了H型栅NMOS器件Kink效应的研究,为PDSOI电路设计中抑制Kink效应提供了有益的参考。

An improved ASM-HEMT model for kink effect on GaN devices

With the analysis of experiment and theory on GaN HEMT devices under DC sweep,an improved model for kink effect based on advanced SPICE model for high electron mobility transistors(ASM-HEMT)is pro⁃posed,considering the relationship between the drain/gate-source voltage and kink effect.The improved model can not only accurately describe the trend of the drain-source current with the current collapse and kink effect,but also precisely fit different values of drain-source voltages at which the kink effect occurs under different gatesource voltages.Furthermore,it well characterizes the DC characteristics of GaN devices in the full operating range,with the fitting error less than 3%.To further verify the accuracy and convergence of the improved model,a load-pull system is built in ADS.The simulated result shows that although both the original ASM-HEMT and the improved model predict the output power for the maximum power matching of GaN devices well,the im⁃proved model predicts the power-added efficiency for the maximum efficiency matching more accurately,with 4%improved.

Observation of Doppler shift f_(D) modulated by the internal kink mode using conventional reflectometry in the EAST tokamak

In this paper we present a new experimental observation using a conventional reflectometry technique,poloidal correlation reflectometry(PCR),in the Experimental Advanced Superconducting Tokamak(EAST).The turbulence spectrum detected by the PCR system exhibits an asymmetry and induced Doppler shift f_(D)during the internal kink mode(IKM)rotation phase.This Doppler shift f_(D)is the target measurement of Doppler reflectometry,but captured by conventional reflectometry.Results show that the Doppler shift f_(D)is modulated by the periodic changes in the effective angle between the probing wave and cutoff layer normal,but not by plasma turbulence.The fishbone mode and saturated long-lived mode are typical IKMs,and this modulation phenomenon is observed in both cases.Moreover,the value of the Doppler shift f_(D)is positively correlated with the amplitude of the IKM,even when the latter is small.However,the positive and negative frequency components of the Doppler shift f_(D)can be asymmetric,which is related to the plasma configuration.A simulated analysis is performed by ray tracing to verify these observations.These results establish a clear link between f_(D)and IKM rotation,and are helpful for studying the characteristics of IKM and related physical phenomena.

Kinking-facilitated nano-crystallization in a shock compressed Mg-1Zn alloy

The local deformation behavior and dynamic recrystallization of a shock compressed Mg-1Zn alloy was investigated through EBSD and TEM.Since dislocation slipping and twinning were locally suppressed during high strain-rate deformation,a more flexible kinking deformation was activated to adjusted local orientation and facilitate slipping and twinning within the kinks.Meanwhile,due to the slow heat dissipation that resulted in a local temperature elevating,the kink bands were evolved into deformation bands with recrystallized nano-grains.Such a finding provides a new perspective for kinking-facilitated nanocrystallization in Mg alloys and other anisotropic metallic materials.

电离辐射中SOI MOSFETs的背栅异常kink效应研究

采用10keVX射线研究了部分耗尽SOIMOSFETs的总剂量辐射效应.实验结果显示,在整个辐射剂量范围内,前栅特性保持良好;而nMOSFET和pMOSFET的背栅对数Id-Vg2曲线中同时出现了异常kink效应.分析表明电离辐射在埋氧/顶层硅(BOX/SOI)界面处产生的界面态陷阱是导致异常kink效应产生的原因.基于MEDICI的二维器件模拟结果进一步验证了这个结论.

C(3,2,2)方程的Compacton解和Kink-Compacton解

为了探讨C(3,2,2)方程中参数对其行波解动力学行为的影响,利用平面动力系统,获得了该方程在不同参数下的孤立波解、Compacton解、Kink波解和Kink-Compacton解,并给出这些解的参数表达式。

SOI-NMOS场效应晶体管的Kink特性分析

本文研究了在室温(RT)、液氮温度(LN)和液氮温度(LHe)下的SOI-NMOS场效应晶体管的电流—电压特性。研究的器件制作在二氧化硅上的经激光退火后的多晶硅薄膜体上。结果表明室温下带有薄膜引出端的晶体管的I_D—V_D特性曲线的Kink形状和液氦下观测到的N-MOS场效应晶体管的Kink形状很类似。实验还表明Kink大小是液氮下比室温下大、液氦下比液氮下的大。应用电容效应,低温下载流子“冻结”机制和不同偏压下载流子产生和复合的物理过程分析可以相应地解释不同温度下Kink效应。

一种能抑制HBT Kink效应的新型复合管

介绍了GaAs异质结双极型晶体管（HBT）的Kink效应及其对宽带匹配的影响,并根据负反馈原理,提出了一种新型的HBT复合管结构。通过对该结构进行小信号分析和计算机软件仿真,该复合晶体管在整个测试频段内输出阻抗接近于一个简单的RC串联电路,并且输出电阻在很宽的频率范围内保持稳定。采用2μm InGaP/GaAs HBT半导体工艺技术流片测试,结果表明,在0.1-20 GHz（接近该HBT的截止频率）的频率范围内所提出的新型HBT复合管抑制了Kink效应并与理论分析结果及计算机仿真结果相吻合。采用该复合管作为宽带放大器的有源器件可以在很大程度上简化匹配电路的设计并且不会显著增加芯片面积和功耗。

Kink效应对低温CMOS读出电路的影响

在深低温下(T<50K),CMOS器件会出现Kink效应,即I-V特性曲线会发生扭曲。当漏源电压较大时(Vds>4V),漏电流突然加大,电流曲线偏离正常的平方关系。本文通过实验表明,Kink效应对CMOS读出电路中的一些电路结构产生较严重的影响,Kink效应会导致源跟随器输出产生严重的非线性;对于共源放大器和两级运放,Kink效应会使其增益产生非线性。最后,针对影响低温读出电路性能的Kink效应进行分析和研究,提出在低温CMOS读出集成电路设计中如何解决这些问题的方案。

LDD工艺参数对多晶硅薄膜晶体管KINK效应的影响

利用Tsuprem4和Medici软件,研究了多晶硅薄膜晶体管的LDD掺杂参数,如掺杂剂量、离子注入能量对KINK效应的影响,得到了它们之间的关系。计算结果表明,随着LDD掺杂剂量的变化,KINK效应对器件的影响是非线性的且存在一个最小值,在掺杂为2×1012cm-2时达到最小。而LDD掺杂能量对KINK效应的影响是线性的,即随着离子注入能量的增加,KINK效应的影响变小。

多晶硅薄膜晶体管kink效应的建模

从kink效应产生的物理机理出发,介绍了目前国内外研究多晶硅薄膜晶体管kink电流所采用的两种主要方法.一种是基于面电荷的方法,另一种是基于求雪崩倍增因子的方法.kink效应具体表现为器件在饱和区跨导和漏电流的显著增加.在数字电路中,kink效应会引起功耗的增加和开关特性的退化;而在模拟电路中,kink效应将降低最大增益和共模抑制比.因此,多晶硅薄膜晶体管kink效应的研究对液晶显示的发展具有重大意义.

纤维卷曲指数和KinK指数对浆张强度的影响

研究了漂白针、阔叶木硫酸盐浆打浆后的纤维卷曲指数和KinK指数，结果表明：纤维卷曲指数和KinK指数是衡量纤维形态的重要指标，打浆能改变纤维的卷曲指数和KinK指数，并对手抄片的强度性能有一定的影响。

多晶硅薄膜晶体管Kink效应研究与建模

多晶硅薄膜晶体管(P-Si TFTs)技术在SOP(system on panel)显示应用中发挥着越来越重要的作用。随着尺寸的不断缩小,P-Si TFT的Kink效应越来越明显,对有源液晶显示矩阵和驱动电路的性能影响很大。对发生Kink效应的物理机制、二维数值仿真及其一维解析模型进行了分析,讨论了晶粒边界、沟道长度与Kink效应的关系,提出建立适合电路仿真的一维解析模型的关键与展望。

Effect of the Plasma Pressure on Magnetohydrodynamic Kink Instability in a Cylindrical Geometry

A semi-analytical method is introduced to study kink instability in cylindrical plasma with line-tied boundary conditions. The method is based on an expansion for magnetohydrodynamics （MHD） equations in one-dimensional （1D） radial eigenvalue problems by using Fourier transforms. The MHD equations then become an ordinary differential equation. This method is applicable to both ideal and non-ideal MHD problem. The effect of plasma pressure （P0） on kink instability is studied in a cylindrical geometry. Complex discrete spectra are pre- sented. Two-dimensional （2D） eigenfunctions with the line-tied boundary conditions are obtained. The growth rate and radial eigenfunctions are different in the two cases of P0 = 0 and P0 ≠ 0, which indicate that the effect of plasma pressure can not be ignored if it is large enough. This method allows us to understand the role of individual radial eigenfunctions, and is also computationally efficient compared to direct solutions of the MHD equations by the finite difference method.

SOI/MOSFET Kink效应的模拟和分析

非全耗尽SOI/MOS晶体管由于存在“Kink效应”而限制了它的应用范围。本文考虑了沟道夹断区的碰撞电离和横向寄生晶体管效应,对浮置衬底SOI/nMOS晶体管的电流—电压特性曲线进行了理论计算,讨论了Kink效应的产生机理。计算结果与实验符合甚好。对器件参数的分析可以定性地指导抑制Kink效应的器件优化设计。

Three-Dimensional Simulation of Plasma Deformation During Contact Opening in a Circuit Breaker,Including the Analysis of Kink Instability and Sausage Instability

A three-dimensional （3-D） transient model has been developed to investigate plasma deformation driven by a magnetic field and its influence on arc stability in a circuit breaker. The 3-D distribution of electric current density is obtained from a current continuity equation along with the generalized Ohm＇s law; while the magnetic field induced by the current flowing through the arc column is calculated by the magnetic vector potential equation. When gas interacts with an arc column, fundamental factors, such as Ampere＇s law, Ohm＇s law, the turbulence model, transport equations of mass, momentum and energy of plasma flow, have to be coupled for aria- lyzing the phenomenon. The coupled interactions between arc and plasma flow are described in the fl＇amework of time-dependent magnetohydrodynamic （MHD） equations in conjunction with a K-~ turbulence model. Simulations have been focused on sausage and kink instabilities in plasma （these phenomena are related tO pinch effects and electromagnetic fields）. The 3-D sjm- ulation reveals the relation between plasma deformation and instability phenomena, which affect arc stability during circuit breaker operation. Plasma deformation is the consequence of coupled interactions between the electromagnetic force and plasma flow described in simulations.

SOI器件的kink效应研究

研究了SOI器件中的kink效应,主要包括不同器件类型、不同体接触结构、沟道长度以及栅氧厚度对kink效应的影响。研究发现NMOS器件由于能够产生较多的电子空穴对,在输出特性曲线中呈现明显的kink效应,而PMOS器件由于空穴的电离率较低,碰撞电离产生的电子-空穴对远低于NMOS器件,它的kink效应不明显。对源体短接、H型栅和T型栅三种不同结构的NMOS器件进行研究,发现T型栅器件kink效应最明显。比较了不同沟道长度对kink效应的影响,发现沟道越短,kink效应越明显。比较了栅氧厚度对kink效应的影响,发现随着栅氧厚度减小,kink效应越明显,这主要是由于隧穿电流引起的。

HEMT的Kink效应和低频偏移效应解析模型

本文在考虑到界面态陷阱的基础上，建立了ＨＥＭＴ的静态和交流小信号解析模型，该模型能够正确地描述ＨＥＭＴ的Ｋｉｎｋ效应和低频偏移效应，并和实验符合相当好．文中还深入讨论了Ｉｎ组分和偏置的影响．

An improved EEHEMT model for kink effect on AlGaN/GaN HEMT

In this paper, a new current expression based on both the direct currect （DC） characteristics of the A1GaN/GaN high election mobility transistor （HEMT） and the hyperbolic tangent function tanh is proposed, by which we can describe the kink effect of the A1GaN/GaN HEMT well. Then, an improved EEHEMT model including the proposed current expression is presented. The simulated and measured results of Ⅰ-Ⅴ, S-parameter, and radio frequency （RF） large-signal characteristics are compared for a self-developed on-wafer A1GaN/GaN HEMT with ten gate fingers each being 0.4-μm long and 125-p-m wide （Such an A1GaN/GaN HEMT is denoted as A1GaN/GaN HEMT （10 × 125 μm））. The improved large signal model simulates the Ⅰ-Ⅴ characteristic much more accurately than the original one, and its transconductance and RF characteristics are also in excellent agreement with the measured data.

Mechanical buckling induced periodic kinking/stripe microstructures in mechanically peeled graphite fla es from HOPG

Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and stripes, were observed in thin graphite flakes that were mechanically peeled from highly oriented pyrolytic graphite. In this paper, a theoretical model is presented to attribute the formation of such ordered structures to the alternation of two mechanical processes during the exfoliation： （1） peeling of a graphite flake and （2） mechanical buckling of the flake being sub- jected to bending. In this model, the width of the stripes L is determined by thickness h of the flakes, surface energy Y, and critical buckling strain ecr. Using some appropriate values of y and ecr that are within the ranges determined by other inde- pendent experiments and simulations, the predicted relations between the stripe width and the flake thickness agree reason- ably well with our experimental measurements. Conversely, measuring the L-h relations of the periodic microstructures in thin graphite flakes could help determine the critical mechan- ical buckling strain εcr and the interface energy γ.