Short-channel single-gate SOI MOSFET model

The authors derive an analytical model for threshold voltage for fully depleted single-gate silicon-on-insulator (SOI) MOSFETs taking into consideration the two-dimensional effects in both SOI and buried-oxide layers. Their model is valid for both long- and short-channel SOI MOSFETs and demonstrates the dependence of short-channel effects on the device parameters of channel-doping concentration, gate oxide, SOI, and buried-oxide thickness. It reproduces the numerical data for sub-0.1-/spl mu/m gate-length devices better than previous models.     

精确的短沟MOSFET电路模型及参数提取

给出一套具有较高精度且同时适用于数字电路和模拟电路ＣＡＤ的短沟ＭＯＳ器件直流模型。该模型精确、高效，可移植到ＨＳＰＩＣＥ等通用线路分析软件中。结合解析和数值两种参数提取方法，文中采用局部优化参数提取法进行ＭＯＳ器件参数提取。优化算法采用单纯形直接搜索法。参数提取过程中考虑了输出电导的精确性。通过对１．２μｍＣＭＯＳ工艺ＮＭＯＳ器件的测试及参数提取，并进行模型计算，结果表明理论和实际值符合很好。     

短沟道MOSFET散粒噪声测试方法研究

针对MOSFET散粒噪声难以测量的特点,提出了一种低温散粒噪声测试方法。在屏蔽环境下,将被测器件置于低温装置内,有效抑制了外界电磁波和热噪声的干扰,采用背景噪声足够低的放大器以及偏置器、适配器等,建立低温散粒噪声测试系统。应用本系统对短沟道MOSFET器件进行噪声测试,分析该器件散粒噪声的特性。     

Complex images of a point charge in rectangular conducting planes

The exact images of a point charge in rectangular conducting planes are discretely located on an infinite plane, making it difficult to compute the electrostatic field rapidly. In the paper, a complex image theory for the electrostatic problem in rectangular conducting planes is investigated. The research shows that only a few complex images are used to replace the countless exact images, but the error is less than 0.2% when they are utilized to compute the electrostatic potential functions, and the execution time is greatly reduced     

A multiple input differential amplifier based on charge sharing on a floating-gate MOSFET

The loseless property of an MOS floating gate is exploited to implementexact summing operations in the charge domain. Loseless charge sharing in such structures yields circuits with potential applications as building blocks for analog signal processing. Large signal as well as small signal models of floating-gate transistors are presented for both above-threshold and subthreshold regions. Experimental data from fabricated devices in a 2 micron double poly, n-well process are in good agreement with the models. A canonical structure, the Multiple Input Floating-gate Differential Amplifier is proposed and its use in different circuit configurations demonstrated. Experimental data from a multiple differential input operational amplifier are presented. Limitations of the proposed circuits are also discussed.This work was partially supported by a NSF Research Initiation Award (MIP-9010364).     

A new simplified charge pumping current model and its modelparameter extraction [MOSFET]

Using the Shockley-Read-Hall (SRH) theory, a simple analytic charge pumping current model has been developed and its accuracy verified by exact numerical analysis. It is shown that the derived analytic charge pumping current model with constant capture cross sections for electrons and holes does not correctly simulate the rising (falling) edges of the experimental charge pumping current. According to the slopes of the logarithmic charge pumping current, effective capture-cross-section models for elections and holes are proposed and are incorporated into the developed analytic charge pumping current model. It is shown that the experimental charge pumping current can be simulated very well by using the modified analytic model     

Silicon transistor ICEOcharacteristics on a curve tracer

It is shown that the loop frequently observed in curve-tracer measurements of ICEOis generated by capacitive currents in the junction capacitances, together with the forward and reverse conduction properties of the emitter-base diode, and is not representative of true ICEO. A true ICEOmeasurement may take several hours.     

The threshold-voltage model of MOSFET devices with localizedinterface charge

A new analytic threshold-voltage model for a MOSFET device with localized interface charges is presented. Dividing the damaged MOSFET device into three zones, the surface potential is obtained by solving the two-dimensional (2-D) Poisson's equation. Calculating the minimum surface potential, the analytic threshold-voltage model is derived. It is verified that the model accurately predicts the threshold voltage for both fresh and damaged devices. Moreover, the Drain-Induced Barrier Lowering (DIBL) and substrate bias effects are included in this model. It is shown that the screening effects due to built-in potential and drain bias dominate the impact of the localized interface charge on the threshold voltage. Calculation results show that the extension, position and density of localized interface charge are the main issues influencing the threshold voltage of a damaged MOSFET device. Simulation results using a 2-D device simulator are used to verify the validity of this model, and quite good agreement is obtained for various cases     

MOSFET 1/f noise model based on mobility fluctuation in linearregion

A new 1/f noise model for MOSFETs in the linear region, based on the Hooge mobility fluctuation noise expression, is presented. Simulation results for the new model are in good agreement with experimental results; thus, the new model can be used to predict and estimate the 1/f noise performance for p-MOSFET devices     

A model for gated-lateral BJTs based on standard MOSFET models

The Pao-Sah MOSFET equation is modified so that it applies when the source-body junction is forward biased. The modified equation can be separated into two components: (1) a MOSFET charge-sheet term and (2) a bipolar transistor term. The role of the two components in the variable gain of gated-lateral bipolar transistors (GL-BJT) is discussed     

基于UML的无线网络镜像模型

镜像能够复现真实的网络环境,帮助开发人员定位系统中的错误以及发现潜在的问题。作为软件工程的标准建模语言,UML可以用于对实际问题进行建模和分析。使用UML对无线网络设备进行建模,并利用UML活动图给出了实际网络微缩镜像算法。基于此方法可以快速地构造高仿真的网络镜像,既压缩了网络规模又能保持网络的重要特征。     

Analysis of the charge pumping technique and its application forthe evaluation of MOSFET degradation

It is shown that the charge pumping technique is able not only to determine the degradation mechanisms in MOS transistors under all kinds of aging conditions (e.g., irradiation, hot-carrier, Fowler-Nordheim stress), but also in several cases to evaluate and to quantify the degradation. It is further shown that the technique can be applied to separate the presence of fixed oxide changes due to charge trapping and the generation of interface traps. It can be used to analyze degradations that occur uniformly over the transistor channel, as well as strongly localized transistor degradations (e.g., for the case of hot-carrier degradations). All possible cases of uniform and nonuniform degradations, for p-channel as well as for n-channel transistors, are described, and for most of them experimental examples are given     

A compact LDD MOSFET I-V model based on nonpinned surface potential

Based on nonpinned surface potential concept, in this paper we present a compact single-piece and complete I-V model for submicron lightly-doped drain (LDD) MOSFETs. The physics-based and analytical model was developed using the drift-diffusion equation and based on the quasi two-dimensional (2-D) Poisson equation. The important short-channel device features: drain-induced-barrier-lowering (DIBL), channel-length modulation (CLM), velocity saturation, and the parasitic series source and drain resistances have been included in the model in a physically consistent manner. In this model, the LDD region is treated as a bias-dependent series resistance, and the drain-voltage drop across the LDD region has been considered in modeling the DIBL effect. This model is smoothly-continuous, valid in all regions of operation and suitable for efficient circuit simulation. The accuracy of the model has been checked by comparing the calculated drain current, conductance and transconductance with the experimental data     

Worn-out oxide MOSFET characteristics: Role of gate current and device parameters on a current mirror

In this work, the influence of gate oxide wear-out and breakdown (BD) on MOSFET output characteristics has been studied for short and long channel transistors. The experimental curves have been fitted to the BSIM4 model and have been introduced in a circuit simulator to study the effect of the oxide wear-out and BD in an analog circuit such as a current mirror. The results show important variations in the behaviour of the current mirror especially for the long channel transistor.     

Adaptive noise reduction of InSAR images based on a complex-valuedMRF model and its application t o phase unwrapping problem

We propose a new adaptive noise reduction method for interferometric synthetic aperture radar (InSAR) complex-amplitude images. In the proposed method, we detect residues (singular points) in the phase image as well as their neighbors at first. Normal areas that contain no residue are used for the estimation of correct pixel values at the marked residues according to 5th order non-causal complex-valued Markov random field (CMRF) model. The process is performed block-wise with the assumption of a locally stationary condition of statistics. Using a CMRF lattice complex-valued neural-network, the error energy defined as the squared norm of distance between signal and estimated values is minimized by LMS steepest descent algorithm. Eventually, the number of residues is decreased. An application is also presented. An InSAR image around Mt. Fuji is processed by the proposed technique and then phase-unwrapped by the branch-cut method. It is found that after the application of the proposed method, a better phase unwrapped image can be obtained successfully     

A generalized tanh law MOSFET model and its applications to CMOSinverters

A generalized tanh law model is proposed to simulate the current-voltage characteristics of both long-channel and short-channel MOS transistors. The proposed model is used to calculate the propagation delay, short-circuit power dissipation, and logic threshold voltage of CMOS inverters. The results obtained are in good agreement with those obtained using classical models     

Adaptive Block-size Transform based Just-Noticeable Difference model for images/videos

In this paper, we propose a novel Adaptive Block-size Transform (ABT) based Just-Noticeable Difference (JND) model for images/videos. Extension from 8×8 Discrete Cosine Transform (DCT) based JND model to 16×16 DCT based JND is firstly performed by considering both the spatial and temporal Human Visual System (HVS) properties. For still images or INTRA video frames, a new spatial selection strategy based on the Spatial Content Similarity (SCS) between a macroblock and its sub-blocks is proposed to determine the transform size to be employed to generate the JND map. For the INTER video frames, a temporal selection strategy based on the Motion Characteristic Similarity (MCS) between a macroblock and its sub-blocks is presented to decide the transform size for the JND. Compared with other JND models, our proposed scheme can tolerate more distortions while preserving better perceptual quality. In order to demonstrate the efficiency of the ABT-based JND in modeling the HVS properties, a simple visual quality metric is designed by considering the ABT-based JND masking properties. Evaluating on the image and video subjective databases, the proposed metric delivers a performance comparable to the state-of-the-art metrics. It confirms that the ABT-based JND consists well with the HVS. The proposed quality metric also is applied on ABT-based H.264/Advanced Video Coding (AVC) for the perceptual video coding. The experimental results demonstrate that the proposed method can deliver video sequences with higher visual quality at the same bit-rates.     

Supervised segmentation of remote sensing images based on a tree-structured MRF model

Most remote sensing images exhibit a clear hierarchical structure which can be taken into account by defining a suitable model for the unknown segmentation map. To this end, one can resort to the tree-structured Markov random field (MRF) model, which describes a K-ary field by means of a sequence of binary MRFs, each one corresponding to a node in the tree. Here we propose to use the tree-structured MRF model for supervised segmentation. The prior knowledge on the number of classes and their statistical features allows us to generalize the model so that the binary MRFs associated with the nodes can be adapted freely, together with their local parameters, to better fit the data. In addition, it allows us to define a suitable likelihood term to be coupled with the TS-MRF prior so as to obtain a precise global model of the image. Given the complete model, a recursive supervised segmentation algorithm is easily defined. Experiments on a test SPOT image prove the superior performance of the proposed algorithm with respect to other comparable MRF-based or variational algorithms.     

基于漏极导通区特性理解MOSFET开关过程

本文先介绍了基于功率MOSFET的栅极电荷特性的开关过程;然后介绍了一种更直观明析的理解功率MOSFET开关过程的方法:基于功率MOSFET的导通区特性的开关过程,并详细阐述了其开关过程.开关过程中,功率MOSFET动态的经过是关断区、恒流区和可变电阻区的过程.在跨越恒流区时,功率MOSFET漏极的电流和栅极电压以跨导为正比例系列,线性增加.米勒平台区对应着最大的负载电流.可变电阻区功率MOSFET漏极减小到额定的值.     

40-Gb/s all-optical wavelength conversion based on a nonlinearoptical loop mirror

All-optical wavelength conversion based on a nonlinear optical loop mirror (NOLM) at 40 Gb/s is demonstrated for the first time. The effect of walkoff time between control beam and signal beams is investigated when the NOLM is used as an all-optical wavelength converter or an all-optical demultiplexer