异质栅非对称Halo SOI MOSFET亚阈值电流模型

在沟道源端一侧引入高掺杂Halo结构的异质栅SOI MOSFET,可以有效降低亚阈值电流.通过求解二维泊松方程,为该器件建立了亚阈值条件下的表面势模型.利用常规漂移.扩散理论,在表面势模型的基础上,推导出新结构器件的亚阈值电流模型.为了求解简单,文中给出了一种分段近似方法,从而得到表面势的解析表达式.结果表明,所得到的表面势解析表达式和确切解的结果高度吻合.二维器件数值模拟器ISE验证了通过表面势解析表达式得到的亚阈值电流模型,在亚阈值区二者所得结果吻合得很好.     

异质栅非对称Halo SOI MOSFET亚阈值电流模型

在沟道源端一侧引入高掺杂Halo结构的异质栅SOI MOSFET,可以有效降低亚阈值电流.通过求解二维泊松方程,为该器件建立了亚阈值条件下的表面势模型.利用常规漂移.扩散理论,在表面势模型的基础上,推导出新结构器件的亚阈值电流模型.为了求解简单,文中给出了一种分段近似方法,从而得到表面势的解析表达式.结果表明,所得到的表面势解析表达式和确切解的结果高度吻合.二维器件数值模拟器ISE验证了通过表面势解析表达式得到的亚阈值电流模型,在亚阈值区二者所得结果吻合得很好.     

一种非对称双栅应变硅HALO掺杂沟道MOSFET阈值电压解析模型

提出了一种非对称双栅应变硅HALO掺杂沟道金属氧化物半导体场效应管结构.该器件前栅和背栅由两种不同功函数的金属构成,沟道为应变硅HALO掺杂沟道,靠近源区为低掺杂区域,靠近漏区为高掺杂区域.采用分区的抛物线电势近似法和通用边界条件求解二维泊松方程,分别求解了前背栅表面势、前背栅表面电场及前背栅阈值电压,建立了双栅器件的表面势、表面电场和阈值电压解析模型.详细讨论了物理参数对解析模型的影响.研究结果表明,该器件能够很好的抑制短沟道效应、热载流子效应和漏致势垒降低效应.模型解析结果与DESSIS仿真结果吻合较好,证明了该模型的正确性.     

短沟道双栅MOSFET的亚阈值特性分析

基于泊松方程和拉普拉斯方程,结合双栅MOSFET的边界条件,采用牛顿-拉夫逊迭代法推导了双栅MOSFET亚阈值区全沟道的电势解析解。在亚阈值区电流密度方程的基础上,提出了双栅MOSFET的一个亚阈值电流模型,并获得了亚阈值摆幅的解析公式。通过对物理模型和数值模拟结果进行比较,发现在不同的器件结构参数下,亚阈值摆幅之间的误差均小于5%。     

复合型栅氧化层薄膜双栅MOSFET研究

通过对硅膜中最低电位点电位的修正,得到复合型栅氧化层薄膜双栅MOSFET亚阈值电流模型以及阈值电压模型。利用MEDICI软件,针对薄膜双栅MOSFET,对四种复合型栅氧化层结构DIDG MOSFET(Dual insulator double gate MOSFET)进行了仿真。通过仿真可知:在复合型结构中,随着介电常数差值的增大,薄膜双栅器件的短沟道效应和热载流子效应得到更有效的抑制,同时击穿特性也得到改善。此外在亚阈值区中,亚阈值斜率也可以通过栅氧化层设计进行优化,复合型结构器件的亚阈值斜率更小,性能更优越。     

一种新型全耗尽双栅MOSFET

提出一种新型全耗尽双栅MOSFET,该器件具有异质栅和LDD结构.异质栅由主栅和两个侧栅组成,分区控制器件的沟道表面势垒.通过Tsuprem-4工艺模拟和Medici器件模拟验证表明,与普通双栅全耗尽SOI相比,该器件获得了更好的开态/关态电流比和亚阈值斜率.在0.18μm工艺下,开态/关态电流比约为1010,亚阈值斜率接近60mV/dec.     

一种新型全耗尽双栅MOSFET

提出一种新型全耗尽双栅MOSFET,该器件具有异质栅和LDD结构.异质栅由主栅和两个侧栅组成,分区控制器件的沟道表面势垒.通过Tsuprem-4工艺模拟和Medici器件模拟验证表明,与普通双栅全耗尽SOI相比,该器件获得了更好的开态/关态电流比和亚阈值斜率.在0.18μm工艺下,开态/关态电流比约为1010,亚阈值斜率接近60mV/dec.     

短沟道三材料柱状围栅MOSFET的解析模型

在柱坐标系下利用电势的抛物线近似,求解二维泊松方程得到了短沟道三材料柱状围栅金属氧化物半导体场效应管的中心及表面电势。推导了器件阈值电压、亚阈值区电流和亚阈值摆幅的解析模型,分析了沟道直径、栅氧化层厚度和三栅长度比对阈值电压、亚阈值区电流和亚阈值摆幅的影响。利用Atlas对具有不同结构参数的器件进行了模拟研究和比较分析。结果表明,基于解析模型得到的计算值与模拟值一致,验证了所建模型的准确性,为设计和应用此类新型器件提供了理论基础。     

纳米MOSFET的多栅结构和应变硅纳米线结构

介绍了在进入22 nm技术节点后MOSFET器件的两个发展方向,即多栅结构和应变硅纳米线结构.首先通过分析特征长度与有效栅极数量的关系,表明多栅结构器件可以有效增强栅极对沟道的控制,抑制短沟道效应,接近理想的亚阈值斜率;然后分析了应变对能带结构的影响,从理论上论述了应变沟道可以显著提高载流子迁移率;最后介绍了悬浮硅纳米...     

非对称异质双栅应变硅MOSFETs 二维模型研究

基于对二维泊松方程的精确求解,本文对全耗尽型非对称异质双栅应变硅MOSFET的二维表面势,表面电场,阈值电压进行了研究。模型结果和二维数值模拟器的结果很吻合。此外并对该器件的物理作了深入的研究。该模型对设计全耗尽型非对称异质双栅应变硅MOSFET器件有着重要的指导作用.     

Analytical Model of Subthreshold Current and Slope for Asymmetric 4-T and 3-T Double-Gate MOSFETs

In this paper, analytical models of subthreshold current and slope for asymmetric four-terminal double-gate (DG) MOSFETs are presented. The models are used to study the subthreshold characteristics with asymmetry in gate oxide thickness, gate material work function, and gate voltage. A model for the subthreshold behavior of three-terminal DG MOSFETs is also presented. The results of the models show excellent match with simulations using MEDICI. The analytical models provide physical insight which is helpful for device design.      

Two-Dimensional Analytical Threshold Voltage and Subthreshold Swing Models of Undoped Symmetric Double-Gate MOSFETs

We have developed analytical physically based models for the threshold voltage [including the drain-induced barrier lowering (DIBL) effect] and the subthreshold swing of undoped symmetrical double-gate (DG) MOSFETs. The models are derived from an analytical solution of the 2-D Poisson equation in which the electron concentration was included. The models for DIBL, subthreshold swing, and threshold voltage roll-off have been verified by comparison with 2-D numerical simulations for different values of channel length, channel thickness, and drain-source voltage; very good agreement with the numerical simulations has been observed     

Analytical model for subthreshold current and subthreshold swing of short-channel double-material-gate MOSFETs with strained-silicon channel on silicon-germanium substrates

The present work gives some insight into the subthreshold behaviour of short-channel double-material-gate strained-silicon on silicon-germanium MOSFETs in terms of subthreshold swing and off-current. The formulation of subthreshold current and, thereupon, the subthreshold swing have been done by exploiting the expression of potential distribution in the channel region of the device. The dependence of the subthreshold characteristics on the device parameters, such as Ge mole fraction, gate length ratio, work function of control gate metal and gate length, has been tested in detail. The analytical models have been validated by the numerical simulation results that were obtained from the device simulation software ATLAS^TM by Silvaco Inc.     

Explicit Analytical Charge and Capacitance Models of Undoped Double-Gate MOSFETs

An analytical, explicit, and continuous-charge model for undoped symmetrical double-gate (DG) MOSFETs is presented. This charge model allows obtaining analytical expressions of all total capacitances. The model is based on a unified-charge-control model derived from Poisson's equation and is valid from below to well above threshold, showing a smooth transition between the different regimes. The drain current, charge, and capacitances are written as continuous explicit functions of the applied bias. We obtained very good agreement between the calculated capacitance characteristics and 2-D numerical device simulations, for different silicon film thicknesses.     

双栅双应变沟道全耗尽SOI MOSFETs的特性分析

提出了一种全新的器件结构--双栅双应变沟道全耗尽SOI MOSFETs,模拟了沟道长度为25nm时器件的电学特性.工作在单栅模式下,应变沟道(Ge=0.3)驱动能力与体Si沟道相比,nMOS提高了43%,pMOS提高了67%;工作在双栅模式下,应变沟道(Ge=0.3)与体Si沟道相比较,驱动电流的提高nMOS为31%,pMOS为60%.仿真结果表明,双栅模式比单栅模式有更为陡直的亚阈值斜率,更高的跨导以及更强的抑制短沟道效应的能力.综合国内外相关报道,该结构可以在现今工艺条件下实现.     

Analytical modelling for the current-voltage characteristics of undoped or lightly-doped symmetric double-gate MOSFETs

An analytical drain current model for undoped (or lightly-doped) symmetric double-gate (DG) MOSFETs is presented. This model is based on the subthreshold leakage current in weak inversion due to diffusion of carriers from source to drain and an analytical expression for the drain current in strong inversion of long-channel DG MOSFETs, both including the short-channel effects. In the saturation region, the series resistance, the channel length modulation, the surface-roughness scattering and the saturation velocity effects were also considered. The proposed model has been validated by comparing the transfer and output characteristics with simulation and experimental results.     

Explicit Continuous Models for Double-Gate and Surrounding-Gate MOSFETs

Explicit continuous models for both double-gate (DG) and surrounding-gate (SG) MOSFETs are presented. These models evolve from previous DG and SG MOSFETs models, which need to solve implicit equations for intermediate parameters by numerical iteration or the table lookup method. By developing approximate explicit solutions for the intermediate parameters, we can express the drain current, terminal charge, transconductance, and transcapacitance as explicit functions of applied voltages as well as the structural parameters. High accuracy and efficiency, combined with inherited favorable features from the previous models, make these new models suitable for circuit simulation programs.     

非掺杂对称双栅的基于完整表面电势的核心模型

通过求解Poisson方程自洽地得到了表面电势随沟道电压的变化关系,从而推出了非掺杂对称双栅MOSFET的一个基于表面势的模型. 通过Pao-Sah积分得到了漏电流的表达式. 该模型由一组表面势方程组成,解析形式的漏电流可以通过源端和漏端的电势得到. 结果标明该模型在双栅MOSFET的所有工作区域都成立,而且不需要任何简化(如应用薄层电荷近似)和辅助拟合函数. 对不同工作条件和不同尺寸器件的二维数值模拟与模型的比较进一步验证了提出模型的精度.     

边缘注入对H型栅SOI pMOSFETs亚阈值泄漏电流的影响

就不同边缘注入剂量对H型栅SOI pMOSFETs亚阈值泄漏电流的影响进行了研究。实验结果表明不足的边缘注入将会产生边缘背栅寄生晶体管,并且在高的背栅压下会产生明显的泄漏电流。分析表明尽管H型栅结构的器件在源和漏之间没有直接的边缘泄漏通路,但是在有源扩展区部分,由于LOCOS技术引起的硅膜减薄和剂量损失仍就促使了边缘背栅阈值电压的降低。     

摄动法研究纳米MOSFETs亚阈值特性

采用了一种新的方法研究纳米金属-氧化物-半导体场效应管(MOSFETs)的亚阈值特性,即正则摄动法.由于在纳米MOSFETs中,常用的耗尽近似和页面电荷模型(charge-sheet model)不再适用,导致泊松方程由线性变成非线性形式.利用正则摄动法求解非线性泊松方程可以得到纳米MOSFETs亚阈值电流和亚阈值摆幅指数依赖外加偏压的解析表达式.通过与二维器件模拟软件MEDICI模拟结果比较,证明了该方法及结果的有效性.