对称薄膜双栅nMOSFET模型的研究

利用对称薄膜双栅MOSFET在阈值电压附近硅膜中的常电位近似,以硅膜达到体反型时的泊松方程为基础,得到一个有效的双栅nMOS器件模型.考虑到薄膜双栅SOI器件的体反型特性,阈值电压处的表面势不再受限于传统的强反型界限(指2倍费米势),并运用跨导最大变化(TC)法对此模型进行分析,得到阈值电压和阈值电压处表面势的详细表达式;另外,还演示了薄膜双栅MOSFET的近乎完美的亚阈值斜率特性,其数值模拟结果与文献实验结果吻合较好.     

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。     

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%。     

对称三材料双栅应变硅MOSFET亚阈值电流与亚阈值斜率解析模型

基于泊松方程和边界条件,推导了对称三材料双栅应变硅金属氧化物半导体场效应晶体管（MOSFET：metal oxide semiconductor field effect transistor）的表面势解析解.利用扩散-漂移理论,在亚阈值区电流密度方程的基础上,提出了亚阈值电流与亚阈值斜率二维解析模型.分析了沟道长度、功函数差、弛豫SiGe层的Ge组份、栅介质层的介电常数、应变硅沟道层厚度、栅介质高k层厚度和沟道掺杂浓度等参数对亚阈值性能的影响,并对亚阈值性能改进进行了分析研究.研究结果为优化器件参数提供了有意义的指导.模型解析结果与DESSIS仿真结果吻合较好.     

基于神经网络的纳米MOSFET反型层载流子密度量子更正

文章提出了基于Levenberg—Marquardt BP神经网络的MOSFET反型层载流子密度量子更正模型．对于较大氧化层厚度范围、Si层厚度范围、栅压范围和掺杂浓度范围的单栅以及双MOSFET．Si反型层备点的载流子量子密度都可以通过经典载流子密度进行快速预测，预测结果与Schrodinger—Poisson程的平均相对误差不超过5％。     

图像传感器像素中MOSFET晶体管的栅感应噪声原理及分析

提出一种CMOS图像传感器像素中MOSFET晶体管的栅感应噪声原理.分析表明MOSFET工作于强反型区的栅感应噪声比工作于亚阈值区明显,但当施加在栅极电压达到3V时,随着ω/ωT 比值的增加,MOSFET工作于亚阈值区的栅感应噪声比工作于强反型区明显.同时详细分析了有源像素(APS)中的RESET晶体管的栅感应噪声的影响并提出抑制栅感应噪声的电路     

CMOS图像传感器像素中MOSFET晶体管的栅感应噪声原理及分析

提出一种CMOS图像传感器像素中MOSFET晶体管的栅感应噪声原理.分析表明MOSFET工作于强反型区的栅感应噪声比工作于亚阈值区明显,但当施加在栅极电压达到3V时,随着ω/ωT比值的增加,MOSFET工作于亚阈值区的栅感应噪声比工作于强反型区明显.同时详细分析了有源像素(APS)中的RESET晶体管的栅感应噪声的影响并提出抑制栅感应噪声的电路.     

一种基于载流子的双栅MOSFET解析模型

提出一种全新的基于载流子求解的双栅MOSFET解析模型. 针对无掺杂对称双栅MOSFET结构，该模型由求解泊松方程的载流子分布和Pao-Sah电流形式直接发展而来. 发展的解析模型完全基于MOSFET的基本器件物理进行直接推导,结果覆盖了双栅 MOSFET所有的工作区:从亚阈到强反型和从线性到饱和区,不需要任何额外假设和拟合参数. 模型的预言结果被2D数值模拟很好地验证，表明该解析模型是一个理想的双栅MOSFET建模架构.     

亚50nm自对准双栅MOSFET的结构设计

描述了一种用综合性方法设计的亚50nm自对准双栅MOSFET,该结构能够在改进的主流CMOS技术上实现.在这种方法下,由于各种因素的影响,双栅器件的栅长、硅岛厚度呈现出不同的缩减限制.同时,侧面绝缘层在器件漏电流和电路速度上表现出特有的宽度效应.建立了关于这种效应的模型,并提供了相关的设计指导.另外,还讨论了一种新型的沟道掺杂设计,命名为SCD.利用SCD的DG器件能够在体反模式和阈值控制间取得较好的平衡.最后,总结了制作一个SADG MOSFET 的指导原则.     

亚50nm自对准双栅MOSFET的结构设计

描述了一种用综合性方法设计的亚50nm自对准双栅MOSFET,该结构能够在改进的主流CMOS技术上实现.在这种方法下,由于各种因素的影响,双栅器件的栅长、硅岛厚度呈现出不同的缩减限制.同时,侧面绝缘层在器件漏电流和电路速度上表现出特有的宽度效应.建立了关于这种效应的模型,并提供了相关的设计指导.另外,还讨论了一种新型的沟道掺杂设计,命名为SCD.利用SCD的DG器件能够在体反模式和阈值控制间取得较好的平衡.最后,总结了制作一个SADG MOSFET 的指导原则.     

Analytical modeling of quantization and volume inversion in thinSi-film DG MOSFETs

A compact physics-based quantum-effects model for symmetrical double-gate (DG) MOSFETs of arbitrary Si-film thickness is developed and demonstrated. The model, based on the quantum-mechanical variational approach, not only accounts for the thin Si-film thickness dependence but also takes into account the gate-gate charge coupling and the electric field dependence; it can be used for FDSOI MOSFETs as well. The analytical solutions, verified via results obtained from self-consistent numerical solutions of the Poisson and Schrodinger equations, provide good physical insight with regard to the quantization and volume inversion due to carrier confinement, which is governed by the Si-film thickness and/or the transverse electric field. A design criterion for achieving beneficial volume-inversion operation in DG devices is quantitatively defined for the first time. Furthermore, the utility of the model for aiding optimal DG device design, including exploitation of the volume-inversion benefit to carrier mobility, is exemplified     

Effects of the inversion-layer centroid on the performance ofdouble-gate MOSFETs

The role of the inversion-layer centroid in a double-gate metal-oxide-semiconductor field-effect-transistor (DGMOSFET) has been investigated. The expression obtained for the inversion charge is similar to that found in conventional MOSFETs, with the inversion-charge centroid playing an identical role. The quantitative value of this magnitude has been analyzed in volume-inversion transistors and compared with the value obtained in conventional MOSFETs. The minority-carrier distribution has been found to be even closer to the interfaces in volume-inversion transistors with very thin films, and therefore, some of the advantages assumed for these devices are ungrounded. Finally, the overall advantages and disadvantages of double-gate MOSFET's over their conventional counterparts are discussed     

On the gate capacitance limits of nanoscale DG and FD SOI MOSFETs

An analytical total gate capacitance C/sub G/ model for symmetric double-gate (DG) and fully depleted silicon-on-insulator (FD/SOI) MOSFETs of arbitrary Si film is developed and demonstrated. The model accounts for the effects of carrier-energy quantization and inversion-layer screening and is verified via self-consistent numerical solutions of the Poisson and Schro/spl uml/dinger equations. Results provide good physical insight regarding C/sub G/ degradation due to quantization and screening governed by device structure and/or transverse electric field for nanoscale DG and FD/SOI MOSFETs. Two limits of C/sub G/ at ON-state are then derived when the silicon film t/sub Si/ approaches zero and infinity. The effect of inversion-layer screening on C/sub G/, which is significant for ultrathin Si-film DG MOSFETs, is quantitatively defined for the first time. The insightful results show that the two-dimensional screening length for DG MOSFETs is independent of the doping density and much shorter than the bulk Debye length as a result of strong structural confinement.     

Modeling and simulation of nanoscale tri-gate MOSFETs including quantum effects

Quantum effects are predominant in tri-gate MOSFETs, so a model should be developed. For the first time, this paper presents the analytical model for quantization effects of thin film silicon tri-gate MOSFETs by using variational approach. An analytical expression of the inversion charge distribution function（ICDF） or wave function for the tri-gate MOSFETs has been obtained. This obtained ICDF is used to calculate the important device parameters, such as the inversion charge centroid and inversion charge density. The results are validated against with the simulation data.     

Inversion-layer capacitance and mobility of very thin gate-Oxide MOSFET's

Inversion-layer capacitance has been experimentally characterized and identified to be the main cause of the second-order thickness-dependence of MOSFET characteristics. Field-dependent channel mobilities of both electrons and holes were independent of gate-oxide thicknesses from 50 to 450 Å, e.g., there is no evidence of the alleged mobility degradation in very thin gate-oxide MOSFET's. Subthreshold slope, insignificantly affected by the inversion-layer capacitance, follows the simple theory down to ∼ 35 Å of oxide thickness. The empirical equations for inversion-layer Capacitance and mobilities versus electric field are proposed.     

Quantum mechanical compact modeling of symmetric double-gate MOSFETs using variational approach

A physics-based analytical model for symmetrically biased double-gate (DG) MOSFETs considering quantum mechanical effects is proposed. Schrödinger's and Poisson's equations are solved simultaneously using a variational approach. Solving the Poisson and Schrödinger equations simultaneously reveals quantum mechanical effects (QME) that influence the performance of DG MOSFETs. The inversion charge and electrical potential distributions perpendicular to the channel are expressed in closed forms. We systematically evaluated and analyzed the potentials and inversion charges, taking QME into consideration, in Si based double gate devices. The effect of silicon thickness variation in inversion-layer charge and potentials are quantitatively defined. The analytical solutions provide good physical insight into the quantization caused by quantum confinement under various gate biases.     

Effects of the inversion layer centroid on MOSFET behavior

The effects of the average inversion-layer penetration, the inversion-layer centroid, on the inversion-charge density and the gate-to-channel capacitance have been analyzed. The quantum model has been used, and a variety of data have been obtained by self-consistently solving the Poisson and Schrodinger equations. An empirical expression for the centroid position that is valid for a wide range of electrical and technological variables has been obtained and has been applied to accurately model the inversion-layer density and capacitance     

新结构MOSFET

和传统平面结构MOSFET相比，新结构MOSFET具有更好的性能(如改善的沟道效应(SCE)，理想的漏诱生势垒降低效应(DIBL)和亚阈值特性)和更大的驱动电流等。文章主要介绍了五种典型的新结构MOSFET，包括平面双栅MOSFET、FinFET、三栅MOSFET、环形栅MOSFET和竖直结构MOSFET。随着MOSFET向亚50nm等比例缩小，这些新结构器件将大有前途。     

Charge-based model for symmetric double-gate MOSFETs with inclusion of channel doping effect

This paper presents a unified charge-based model for symmetric double-gate (DG) MOSFETs with a wide range of channel doping concentrations. From one dimensional (1D) Poisson–Boltzmann equation in the DG MOSFET structure, an accurate inversion charge model is proposed, which predicts the inversion charge density precisely from weak inversion, through moderate inversion and finally to strong inversion region for both heavily doped and lightly doped condition. Based on that, the unified drain current model is developed from Pao-Sah’s dual integral. The unified terminal charge and trans-capacitance models are derived out from Ward and Dutton’s linear-charge-partition scheme. Extensive numerical simulations are performed on DG MOSFETs to verify the unified charge-based models and good agreements between them are obtained, proving the validity of the proposed model for further circuit simulation.