An improvement to computational efficiency of the drain current model for double-gate MOSFET

As a connection between the process and the circuit design, the device model is greatly desired for emerging devices, such as the double-gate MOSFET. Time efficiency is one of the most important requirements for device modeling. In this paper, an improvement to the computational efficiency of the drain current model for double-gate MOSFETs is extended, and different calculation methods are compared and discussed. The results show that the calculation speed of the improved model is substantially enhanced. A two-dimensional device simulation is performed to verify the improved model. Furthermore, the model is implemented into the HSPICE circuit simulator in Verilog-A for practical application.     

A novel 10-nm physical gate length double-gate junction field effect transisto

A novel double-gate （DG） junction field effect transistor （JFET） with depletion operation mode is proposed in this paper. Compared with the conventional DG MOSFET, the novel DG JFET can achieve excellent performance with square body design, which relaxes the requirement on silicon film thickness of DG devices. Moreover, due to the structural symmetry, both p-type and n-type devices can be realized on exactly the same structure, which greatly simplifies integration. It can reduce the delay by about 60% in comparison with the conventional DG MOSFETs.     

Extraordinarily high drive currents in asymmetrical double-gate MOSFETs

Numerical simulation results derived from a Schrödinger–Poisson tool applied to scaled double-gate (DG) MOSFETs, supplemented by analytical characterizations of the pertinent physics, are presented to give insight concerning the near-ideal features of DG devices and to explain how the low-voltage drive current of the asymmetrical DG MOSFET, having only one predominant channel, can be comparable to, and even higher than, that of the symmetrical-gate counterpart designed to have the same off-state current.     

Extensive numerical study of the anomalous dynamic scaling of the Wolf-Villain model

In order to study the microscopic physical mechanisms of roughness surfaces exhibiting the anomalous scaling behavior, the Wolf-Villain model in 1+1 and 2+1 dimensions is investigated by the kinetic Monte-Carlo simulation on long time and large length scale (the growth time and the system size are respectively extended to t=2²⁹, for 1+1 dimensions, and t=2²¹, L×L=512×512 for 2+1 dimensions). In the 2+1-dimensional simulations, the noise reduction technique is employed so as to eliminate the crossover effects in the growth process. Our calculations show that the Wolf-Villain model in 1+1 dimensions very probably exhibits intrinsic anomalous scaling behavior in the time and length simulation range of this paper, and the 2+1-dimensional Wolf-Villain model leads to a pyramidal mounded morphology. Some properties of the mounded pattern in the 2+1-dimensional Wolf-Villain model are discussed in the final part of this presentation.     

4H-SiC MOSFET的温度特性研究

对4HSiCMOSFET的器件结构和温度特性进行了研究,总结了器件的结构参数对特性的影响,比较了不同温度下的输出特性以及饱和漏电流、阈值电压、跨导、导通电阻与温度的变化关系,模拟结果表明4HSiCMOSFET具有优异的温度特性,在800K下可以正常工作 关键词： 4H-SiC MOSFET     

Finite-size scaling corrections for the eight-vertex model

Finite-size scaling corrections are calculated analytically for two of the maximal eigenvalues of the transfer matrix in the isotropic eight-vertex model. The valuec=1 for the conformal anomaly of the Virasoro algebra is confirmed.     

单管体硅,SOI及DSOI MOSFET热分析

本文简单介绍了SOI和 DSOI半导体器件制造技术,并提出了单管体硅,SOI及 DSOI MOSFET的热阻模型。进而对体硅,SOI MOSFET器件,特别是DSOI MOSPET的热学特性进行数值计算,比较并分析了其数值计算结果。     

45 nm MOSFET毫米波小信号等效电路模型参数提取技术

为了有效地表征45 nm MOSFET毫米波频段下的电学特性,研究了其高频等效电路的建模方法。基于45 nm MOSFET的器件物理结构及其导纳参数分析,通过综合考虑器件的本征物理特性、管脚及测试寄生特性,提出了一种准静态近似的高频等效电路模型及其参数直接提取的高精度简化算法,以此来统一表征模型参数从强反型区到弱反型区的偏置依赖性,并使之在不同偏置条件下的特性表征具有良好的连续性,以便于移植到商业仿真设计自动化工具中。通过ADS2013仿真工具的散射参数模拟结果与测量数据的一致性比较,验证了所建模型的实用性及其参数提取算法的准确性, 并表征了45 nm器件的偏置依赖性。     

基于场效应管与阶跃恢复二极管的皮秒级脉冲源设计

针对已有脉冲源无法兼顾脉冲宽度和幅值的现象,提出一种基于场效应管（MOSFET）和阶跃恢复二极管（SRD）相结合的皮秒级脉冲源设计方案。通过研究分析传统的几种脉冲源的设计方案,设计出一种百伏级的高重频皮秒级脉冲发生器,在PSPICE上对设计方案进行仿真并制作出脉冲源PCB板,实测在2 MHz的重频下产生半幅脉宽约为400 ps、幅度110 V以上的极窄脉冲,波形稳定,为高分辨的超宽带探测雷达发射机的设计提供了新的选择方案。     

Universal scaling results for the plateau-insulator transition in the quantum Hall regime

The plateau-insulator (PI) transition in the quantum Hall regime, in remarkable contrast to the plateau-plateau (PP) transition, exhibits very special features that enable one for the first time to disentwine the quantum critical aspects of the electron gas (scaling functions, critical indices) from the sample dependent effects of macroscopic inhomogeneities (contact misalignments, density gradients). In this communication we report new experimental data taken from the PI transition of a low-mobility InGaAs/InP heterostructure and propose universal scaling functions for the transport coefficients. Our new findings elucidate fundamental theoretical aspects of quantum criticality that have so far remained inaccessible.     

Heat transfer enhancement in MOSFET mounted on different FR4 substrates by thermal transient measurement

Miniaturization of electronic package leads to high heat density and heat accumulation in electronics device, resulting in short life time and premature failure of the device. Junction temperature and thermal resistance are the critical parameters that determine the thermal management and reliability in electronics cooling. Metal oxide field effect transistor (MOSFET) is an important semiconductor device for light emitting diode-integrated circuit (LED IC) driver application, and thermal management in MOSFET is a major challenge. In this study, investigations on thermal performance of MOSFET are performed for evaluating the junction temperature and thermal resistance. Suitable modifications in FR4 substrates are proposed by introducing thermal vias and copper layer coating to improve the thermal performance of MOSFET. Experiments are conducted using thermal transient tester (T3ster) at 2.0 A input current and ambient temperature varying from 25 ℃to 75 °C. The thermal parameters are measured for three proposed designs: FR4 with circular thermal vias, FR4 with single strip of copper layer and embedded vias, and FR4 with I-shaped copper layer, and compared with that of plain FR4 substrate. From the experimental results, FR4_I-shaped shows promising results by 33.71% reduction in junction temperature and 54.19% reduction in thermal resistance. For elevated temperature, the relative increases in junction temperature and thermal resistance are lower for FR4_I-shaped than those for other substrates considered. The introduction of thermal vias and copper layer plays a significant role in thermal performance.     

Evaluation of the applicability of MOSFET detectors in radiotherapy

MOSFET detectors of 1 mVcGy⁻¹ sensitivity were tested for the accuracy of absorbed dose measurements in radiation therapy with the use of photon and electron beams. Before a detector was used in the study, several calibration coefficients were determined to allow for different factors affecting its operation. Then, the detector exposure response was compared with the dose calculated in the anthropomorphic phantom by the Monaco and MasterPlan treatment planning systems. MOSFET detectors were placed inside the phantom during the irradiation. Three different plans for thorax and pelvis areas were studied. The paper presents the differences between planned and MOSFET measured doses delivered to the selected target areas using conventional and IMRT techniques.     

Finite-size scaling for the mean spherical model with inverse power law interaction

A new analytical technique based on integral transformations with Mittag-Leffler-type kernels is used to derive the finite-size scaling function for the free energy per particle of the mean spherical model with inverse power law asymptotics of the interaction potential. The asymptotic formation of the singularities in the specific heat and magnetic susceptibility at the bulk critical point is studied.     

谐振子基在复标度方法中的应用

在利用薛定谔方程求解共振态能量的过程中，成功的将谐振子基应用于复标度方法，求 解出共振态的能量公式，并以一个比较成熟的势作为检验势，得出比较精确的结果，也作出共振态能量在复能量坐标系中的能量分布。对其中的两个参数基数N和转动角µ进行讨论与分析，验证了共振态的一个原理：在对共振态的计算过程中，计算参数的改变不会影响共振态的位置。     

毫米波频段下MOSFET漏极电流噪声的统一模型

纳米级金属氧化物半导体场效应晶体管(MOSFET)精确的高频噪声模型是毫米波集成电路低功耗设计的重要基础,而现有的高频漏极噪声模型不仅没有融合器件的衬底效应和栅电阻效应,也没有充分考虑器件的频率和偏置依赖性。针对上述问题,基于纳米MOSFET器件的物理特性,并结合漂移扩散方程和有效栅极过载,建立统一表征强反区到弱反区的频率和偏置依赖性的漏极噪声模型,使之便于移植到先进设计系统(ADS)仿真设计。通过所建模型的仿真结果与实验测试结果进行比较,验证所建模型的准确性。同时比较所建模型对130 nm和40 nm MOSFET两种不同工艺器件的实用性,验证其对表征40 nm MOSFET的毫米波噪声特性的优越性。     

Finite-size scaling for Potts models

Recently, Borgs and Kotecký developed a rigorous theory of finite-size effects near first-order phase transitions. Here we apply this theory to the ferromagneticq-state Potts model, which (forq large andd2) undergoes a first-order phase transition as the inverse temperature is varied. We prove a formula for the internal energy in a periodic cube of side lengthL which describes the rounding of the infinite-volume jumpE in terms of a hyperbolic tangent, and show that the position of the maximum of the specific heat is shifted by _m (L)=(Inq/E)L ^–d +O(L ^–2d ) with respect to the infinite-volume transition point _t . We also propose an alternative definition of the finite-volume transition temperature _t (L) which might be useful for numerical calculations because it differs only by exponentially small corrections from _t .     

Finite-size scaling of the three-state Potts model on a simple cubic lattice

Finite-size scaling is studied for the three-state Potts model on a simple cubic lattice. We show that the specific heat and the magnetic susceptibility scale accurately as the volume. The correlation length exhibits behaviors expected for a genuine first-order transition; the one extracted from the unsubtracted correlation function shows a characteristic finite-size behavior, whereas the physical correlation length that characterizes the first excited state stays at a finite value and is discontinuous at the transition point.     

Finite-size scaling in a microcanonical ensemble

The finite-size scaling technique is extended to a microcanonical ensemble. As an application, equilibrium magnetic properties of anL×L square lattice Ising model are computed using the microcanonical ensemble simulation technique of Creutz, and the results are analyzed using the microcanonical ensemble finite-size scaling. The computations were done on the multitransputer system of the Condensed Matter Theory Group at the University of Mainz.     

A two-dimensional analytical subthreshold behavior model for junctionless dual-material cylindrical surrounding-gate MOSFETs

A two-dimensional analytical subthreshold behavior model for junctionless dual-material cylindrical surrounding- gate （JLDMCSG） metal-oxide-semiconductor field-effect transistors （MOSFETs） is proposed. It is derived by solving the two-dimensional Poisson＇s equation in two continuous cylindrical regions with any simplifying assumption. Using this analytical model, the subthreshold characteristics of JLDMCSG MOSFETs are investigated in terms of channel electro- static potential, horizontal electric field, and subthreshold current. Compared to junctionless single-material cylindrical surrounding-gate MOSFETs, JLDMCSG MOSFETs can effectively suppress short-channel effects and simultaneously im- prove carrier transport efficiency. It is found that the subthreshold current of JLDMCSG MOSFETs can be significantly reduced by adopting both a thin oxide and thin silicon channel. The accuracy of the analytical model is verified by its good agreement with the three-dimensional numerical simulator ISE TCAD.     

非对称HALO掺杂栅交叠轻掺杂漏围栅MOSFET的解析模型

为抑制短沟道效应和热载流子效应, 提出了一种非对称HALO掺杂栅交叠轻掺杂漏围栅MOSFET新结构. 通过在圆柱坐标系中精确求解三段连续的泊松方程, 推导出新结构的沟道静电势、阈值电压以及亚阈值电流的解析模型. 结果表明, 新结构可有效抑制短沟道效应和热载流子效应, 并具有较小的关态电流. 此外, 分析还表明栅交叠区的掺杂浓度对器件的亚阈值电流几乎没有影响, 而栅电极功函数对亚阈值电流的影响较大. 解析模型结果和三维数值仿真工具ISE所得结果高度符合.