电场耦合电能传输系统层叠式耦合机构漏电场抑制方法

随着电场耦合电能传输(ECPT)系统功率和传输距离的提高,系统耦合机构极板上的电压也会不断增大,给周围环境带来漏电场辐射问题。针对耦合机构漏电场抑制问题,文中提出了一种新型的层叠式耦合机构。在对新型层叠式耦合机构进行建模分析的基础上,以双侧LC补偿网络的ECPT系统为例,推导了极板电压的计算表达式。对耦合机构外侧极板电压的主要影响因素进行分析,提出了一种以抑制系统漏电场为目标并兼顾系统传输性能的系统参数设计方法。通过仿真,验证了所提出的耦合机构及参数设计方法对漏电场抑制的可行性和有效性。

辐射感生场氧漏电流对CMOS运算放大器特性的影响

介绍了不同版图结构制作的 CMOS运放电路的电离辐照实验结果 ,分析比较了在常规版图及采用了保护环措施后制作的运放电路辐照响应之间的差异。结果显示 ,常规版图制作的运放电路 ,由于存在不易消除的场氧漏电 ,其电路的辐射敏感性会明显增大。而加入保护环后 ,能明显消除这一不利影响 ,从而使电路的抗辐照特性得到改善。

提高地电观测线路抗漏电影响的有效途径

本文对漏电场进行了系统计算,给出漏电场的空间分布特征;对供电线与测量线间的漏电及其转化进行了理论分析,在此基础上讨论了提高地震台站观测线路抗漏电影响适合地震电法特点的较科学经济的布线原则和方法。荷泽地震台线路改造实例及某些实验结果证明了方法的可行性及其效果。

具有垂直漏极场板的GaN HEMT器件结构设计

设计并研究了一种带有由表面漏极场板和垂直漏极场板组成的复合漏极场板的GaN HEMT器件结构。表面漏极场板能在栅漏之间引出新的表面电场峰值从而进一步提高表面电场的分布,而垂直漏极场板通过在体内引入漏极侧纵向电场峰值也能提高栅漏间的表面电场分布,如再结合表面漏极场板就能在二维方向上实现对器件漏电极区域附近电场的调制作用。采用仿真软件Sentaurus TCAD进行仿真和优化,结果表明:在器件栅漏间距为6μm的条件下,通过添加长度为0.5μm的栅极场板、0.2μm的表面漏极场板和1.8μm的垂直漏极场板以及长度为1.7μm、厚度为0.1μm、距离栅电极为0.1μm、掺杂浓度为5×1017 cm-3的P型GaN埋层,器件的击穿电压最大值能达到1 531 V。

Effectof Neutral Traps on Tunneling Current and SILC in Ultrathin Oxide Layer

The effect of neutral trap on tunneling currentin ultrathin MOSFETs is investigated by num erical analy- sis.The barrier variation arisen by neutral trap in oxide layer is described as a rectangular potential well in the con- duction band of Si O2 .The different barrier variation of an ultrathin metal- oxide- sem iconductor(MOS) structure with oxide thickness of4nm is numerically calculated.It is shown that the effect of neutral trap on tunneling cur- rent can not be neglected.The tunneling current is increased when the neutral trap exists in the oxide layer.This simple m odel can be used to understand the occurring mechanism of stress induced leakage current.

SILC Mechanism in Degraded Gate Oxide of Different Thickness

It is shown that traps are generated asymmetrically in the thin gate oxides with different thickness during high field degradation,as well as the multi-mechanism plays role in the Stress Induced Leakage Current (SILC).These factors perform differently in gate oxide of different thickness.A comparison is drew between several analyzing models.Trap assisted tunneling is preferred for thinner samples,while Pool-Frankel like mechanism or thermal emission mechanism should apply to the thick ones.

A Novel Empirical Model of I-V Characteristics for LDD MOSFET Including Substrate Current

A compact model for LDD MOSFET is proposed,which involves the hyperbolic tangent function description and the physics of device with emphasis on the substrate current modeling.The simulation results demonstrate good agreement with measurement,and show that deep submicron LDD MOSFET has larger substrate current than submicron device does.The improved model costs low computation consumption,and is effective in manifestation of hot carrier effect and other effects in deep submicron devices,in turn is suitable for design and reliability analysis of scaling down devices.

Three-dimensional forward modeling and response characteristics analysis of foundation pit leakage electric-field considering electrokinetic effect

The traditional ground direct current method is not suitable for leakage detection of underground diaphragm walls in foundation pits because of its low accuracy and poor anti-noise ability.Here,we propose a joint surface-borehole observation device for leakage electric fi eld detection to achieve rapid measurement of the electric fi eld distribution characteristics at ground level in the foundation pit,thus enabling rapid localization of leakage points.We first establish the mechanism and basic equation of the leakage electric field response by combining the electric field formed by electrokinetic effect(EK)and the stable electric fi eld formed by conduction current in a combined leakage channel.Then,the fi nite–infi nite element coupling method is used to solve the electric fi eld equation to simulate the responses of a three-dimensional foundation pit leakage model.Furthermore,we conduct numerical simulations of diff erent pit models to investigate the infl uencing factors of the detection device and response characteristics of the change in the properties of the leakage channel.The results demonstrate that the proposed joint surface-borehole observation device can effi ciently reveal anomalous potential caused by leakage,and the amplitude of the electric fi eld generated by EK can eff ectively strengthen the leakage electric fi eld signal at the leakage,thus improving detection accuracy and effi ciency.

Degradation of P-MOSFETs Under Off-State Stress

The hot carrier effects under off- state stress m ode( Vgs=0 ,Vds<0 ) have been investigated on9nm P- MOSFETs with channel length varying from1.0 2 5 μm to0 .5 2 5 μm.Both on- and off- state currents are discussed. It is found that the off- state leakage current decreases after a higher voltage stressing,which is induced by the charge injection occurred close to the drain junction.However,the leakage current increases after a lower voltage stressing because of the newly generated interface traps.It is also found that the on state saturation current and threshold voltage degrade significantly with the stress tim e,which we believe is due to the charges injected near the gate- drain overlapping region and/ or the stress- induced interface trap generation.The degradation of Idsatcan be ex- pressed as a function of the product of the gate current( Ig) and the num ber of charges injected into the gate oxide ( Qinj) in a simple power law.Finally,a lifetime prediction model based on the degradation of Idsatis proposed.

High voltage DC leakage detection for double-lined hazardous waste landfill based on finite element method

According to the structural characteristics of hazardous waste landfill, a new model based on the finite element method （FEM） is developed. The detection layer is considered as a sealed space and it is assumed that total current flows through the leak for the high resistivity of geomembrane liner. The leak current is regarded as a positive point current ＋I and the other current source is -I. Electrical potential of an arbitrary point in detection layer satisfies Poisson equation. Experiments for detecting leaks in liner were carried out. Excellent agreement between experimental data and simulated model data validates the new model. Parametric curves for a single leak show that with optimum selection of field survey parameters leaks can be detected effectively. For multiple leaks, the simulated results indicate that they are detectable when leak separation is larger than measurement spacing.

Sealed model and computation of hazardous waste landfill high voltage DC leakage detection

According to the structural characteristics of hazardous waste landfill and the leakage current model of high voltage DC Landfill leakage detection, a sealed model is established detail. The detection layer of the hazardous waste landfill is considered as a sealed assumed that the source current flows through the leak entirely. The leak is regard and analyzed in space and it is ed as a positive current resource ＋ I located at the current entrance or a negative resource - I located at the current exit, which depends on the placement of the current supply. The electrical potential of an arbitrary in detection layer satisfies Poisson equation. The boundary condition is regarded as a natural bound- ary condition for the high resistivity of high density polyethylene （HDPE） membrane. Based on which a numerical calculation method is developed. Satisfactory agreement between experimental da- ta and simulated data validates the analysis. Parametric studies show that a larger horizontal distance between the power supply electrode and leak and a smaller distance between the detector electrodes and the detected liner are helpful to leak location. More parametric curves show that parameters leaks can be detected effectively with optimum selection of field survey.

Gate leakage current of NMOSFET with ultra-thin gate oxide

As dimensions of the metal-oxide-semiconductor field-effect transistor (MOSFET) are scaling down and the thickness of gate oxide is decreased,the gate leakage becomes more and more prominent and has been one of the most important limiting factors to MOSFET and circuits lifetime.Based on reliability theory and experiments,the direct tunneling current in lightly-doped drain (LDD) NMOSFET with 1.4 nm gate oxide fabricated by 90 nm complementary metal oxide semiconductor (CMOS) process was studied in depth.High-precision semiconductor parameter analyzer was used to conduct the tests.Law of variation of the direct tunneling (DT) current with channel length,channel width,measuring voltage,drain bias and reverse substrate bias was revealed.The results show that the change of the DT current obeys index law;there is a linear relationship between gate current and channel dimension;drain bias and substrate bias can reduce the gate current.