谐振隧穿二极管的两种高频小信号模型比较与分析

讨论了谐振隧穿二极管(RTD)的两种微波等效电路模型:类江崎隧道模型(QETM)和量子阱注入传输模型(QWITM)之间的差异,并用最小二乘法拟合实验数据,提取了两种模型的电路参数.理论分析和对拟合结果的比较都说明QWITM比QETM 更加精确,而提取到的QWITM的电路参数的合理性也证明了这一点.在此基础上计算了阻性频率fR,并简单介绍fR的影响因素及其提高方法.     

RTD交流小信号等效电路模型——共振隧穿器件讲座(7)

RTD交流小信号等效电路模型是分析RTD交流特性的基础,也是用网络分析仪测量S参数,拟合提取交流参数和计算截止频率fR的依据。精确、合理的等效电路模型有助于深入理解RTD的工作原理,也对RTD器件和RTD集成电路的设计起重要的指导作用。介绍了四种常见而又重要的RTD交流小信号等效电路模型。     

基于双结模型非理想太阳能电池伏安特性参数数值分析

提出了一种对于太阳电池光照条件和暗特性条件下对其伏安特性全段进行拟合提取参数的改进方法.对太阳电池J-V曲线进行分段, 提取每段的4个关键参数: 串联电阻(Rs)、并联电阻(Rsh)、品质因子(n)、反向饱和电流密度(J0).这种方法采用了双结电路模型法, 并以CdS/CdTe薄膜电池为例进行了光照下和暗特性分析, 得到了比单结电流模型更多的参数, 并且具有较高的拟合精度(误差<0.7%).     

PIN光探测器的小信号电路模型参数的提取

提出了一种利用自适应遗传算法提取p-i-n光探测器小信号电路模型参数的方法.文章首先根据p-i-n光探测器的物理结构确定其等效电路模型,进而采用自适应遗传算法对测量的S参数进行拟合,提取模型参数.自适应遗传算法自动优化交叉概率和变异概率,避免了以往遗传算法中易早熟的缺点.利用该法成功提取出模型的10个参数,建立光探测器小信号电路模型.在130 MHz～20 GHz范围内的实验结果表明,模型仿真结果和测量结果相吻合,证明了这种参数提取方法的可靠性.     

RF螺旋电感参数的提取方法

射频集成电路(RFIC)中电感元件十分重要,其模型是RFIC模拟的关键.在确定电感的电路模型后,要进行正确的设计和优化,还必须知道模型中各元件的参数.文中首先给出了电感结构的嵌入式和非嵌入式电路模型,然后从已知的S参数通过三种途径提取了模型中集总元件参数,并对三种途径提取的元件参数进行了模拟,以便得到提取模型参数的最佳途径.     

VDMOS场效应晶体管电路模型的构造及参数提取

从VDMOS的物理结构出发建立子电路模型,进而导出描述其交直流特性的参数及模型公式.相对以往文献的结果,该模型避免了过多工艺参数的引入,同时对子电路进行了有效的简化.在参数提取软件中的加载结果表明,该模型结构简单,运算速度快,物理概念清晰,拟合曲线与测试数据符合精度高(直流误差5%以内,交流误差10%以内),适于在电路模拟及参数提取软件中应用.     

VDMOS场效应晶体管电路模型的构造及参数提取

从VDMOS的物理结构出发建立子电路模型,进而导出描述其交直流特性的参数及模型公式.相对以往文献的结果,该模型避免了过多工艺参数的引入,同时对子电路进行了有效的简化.在参数提取软件中的加载结果表明,该模型结构简单,运算速度快,物理概念清晰,拟合曲线与测试数据符合精度高(直流误差5%以内,交流误差10%以内),适于在电路模拟及参数提取软件中应用.     

GaN HEMT开关器件小信号模型

GaN高电子迁移率晶体管(HEMT)开关器件模型的研究对提高电路性能和缩短研发周期有着重要的意义.为了开发更加精确的电路模型,基于AlGaN/GaN HEMT开关器件的物理结构得到其等效电路模型.利用不同的方法提取开关器件的寄生电容、寄生电感以及寄生电阻.对于栅极附加有千欧姆量级偏置电阻的开关器件提出了一种新的本征参数提取方法.最后通过引入误差因子来评估该模型的准确性和应用在单刀双掷(SPDT)开关电路中检验模型的正确性.结果表明,误差因子E11 =E22＜2.96％,E12 =E21 ＜1.27％,开关电路拟合S参数与实测S参数结果基本吻合.所设计的小信号模型对未来GaN基电路设计提供了一定的理论指导.     

微波场效应管Ⅰ—Ⅴ特性模型研究

本文对微波场效应管Ⅰ—Ⅴ特性模型进行了研究,分析比较了八种常用模型的优缺点,它可为微波电路的设计提供一个实用的参考依据.在模型参数提取中,我们采用了一种新算法,先应用一个基于主成份灵敏度分析的空间坐标变换,然后采用Levenberg-Marquardt算法进行优化拟合.实际计算表明,此法能够快速、精确地提取模型参数.     

RTD基高速多值量化器的设计

建立的RTD SPICE模型,与实际制作的GaAs基RTD器件进行了拟合验证.对四值量化器电路的工作原理进行了解释说明,通过器件参数的提取,对电路进行了模拟仿真,确定了电路相关参数.通过公式计算得出的电路阈值电压与模拟结果一致.最后对电路最大的工作频率进行了分析.     

Extraction and evolution of Fowler-Nordheim tunneling parameters of thin gate oxides under EEPROM-like dynamic degradation

A new method is presented for the extraction of the Fowler-Nordheim (FN) tunneling parameters of thin gate oxides from experimental current-voltage characteristics of Metal-Oxide-Semiconductor (MOS) capacitors. In this technique, the classical low temperature FN current model is considered but an improved numerical procedure has been implemented for the calculation of the oxide electric field — gate voltage relationship. It is shown that this iterative method leads to an excellent fit of experimental data with theoretical curves for both p-type and n-type substrates, even in the case of high doping levels. The procedure allows the determination of both FN tunneling parameters and potential barrier heights at silicon and polysilicon interfaces with a systematic estimation of the statistical fitting errors on each parameter. It is applied here to the study of the variations of the FN tunneling parameters of thin oxides submitted to EEPROM-like dynamic degradation.     

Double-barrier resonant tunneling transport model

A semiquantum transport model for electron transport in the resonant tunneling diode (RTD) is presented. The total electrons tunneling through the RTD are partitioned into two parts. The first is the coherent tunneling electrons, which do not experience any scattering except by the barriers during tunneling. These electrons are described by the damped resonant tunneling model. The second is the incoherent tunneling electrons, which are the electrons scattered in the quantum well by the phonons, impurities, etc. The hot electron distribution, which is characterized by the effective Fermi energy μ_e and electron temperature T_e, is proposed to model the nonequilibrium distribution of the incoherent electrons in the well. The parameters μ_e and T_e can be uniquely determined by applying the energy conservation law and the particle conservation law to the incoherent electrons in the well. The incoherent electrons play a major role in the operation of the RTD. The capacitance of the RTD is investigated, based on the model and Poisson's equation. Extensive numerical results are presented     

GaAs-AlxGa1-xAs双势垒结构中电子共振隧穿寿命

采用转移矩阵和数值计算相结合的方法求解含时Schrodinger方程，计算了电子在双势垒结构中的构建时间和隧穿寿命. 结果表明：构建时间和隧穿寿命对于描述电子隧穿时间特性同等重要. 通过研究隧穿时间对结构参数的依赖情况发现，隧穿寿命随阱宽和垒厚的增加而迅速增大.     

Model and analysis of gate leakage current in ultrathin nitridedoxide MOSFETs

An analytical model of the gate leakage current in ultrathin gate nitrided oxide MOSFETs is presented. This model is based on an inelastic trap-assisted tunneling (ITAT) mechanism combined with a semi-empirical gate leakage current formulation. The tunneling-in and tunneling-out current are calculated by modifying the expression of the direct tunneling current model of BSIM. For a microscopic interpretation of the ITAT process, resonant tunneling (RT) through the oxide barrier containing potential wells associated with the localized states is proposed. We employ a quantum-mechanical model to treat electronic transitions within the trap potential well. The ITAT current model is then quantitatively consistent with the summation of the resonant tunneling current components of resonant energy levels. The 1/f noise observed in the gate leakage current implies the existence of slow processes with long relaxation times in the oxide barrier. In order to verify the proposed ITAT current model, an accurate method for determining the device parameters is necessary. The oxide thickness and the interface trap density of the gate oxide in the 20-30 Å thickness range are evaluated by the quasi-static capacitance-voltage (C-V) method, dealing especially with quantum-mechanical and polysilicon effects     

光伏型碲镉汞长波探测器暗电流特性的参数提取研究

报道了一种适用于碲镉汞长波光伏探测器的由典型电阻电压(R-V)曲线提取器件基本特征参数的数据处理途径.拟合程序中采用的暗电流机制包括了扩散电流机制,产生复合电流机制,陷阱辅助隧穿机制以及带到带直接隧穿电流机制.本文详细地给出了该拟合计算所采用的方法和途径,分析了拟合参数的误差范围.通过对实际器件的R-V特性曲线的拟合计算,给出了实际器件的基本特征参数,验证了该数据处理途径的实用性.     

Equivalent circuit parameters of resonant tunneling diodesextracted from self-consistent Wigner-Poisson simulation

The equivalent circuit parameters of resonant tunneling diodes (RTD) are extracted from numerical simulation results for RTDs. The RTD models used in this paper are double barrier structures. The influence of the resonant tunneling structure (RTS) parameters, such as the height of barriers, the width of the quantum well, the width of the spacers, and the width of the barriers, on the device parameters are systematically discussed. The effects of device temperature on device parameters are also discussed. Scattering between electrons and phonons greatly affects device parameters and thereby the function of the RTDs. Physical explanations about how the structure parameters and device temperature influence the device parameters are provided. Based on the analysis results, a general way to get an RTD oscillator with a higher maximum frequency is suggested     

Analysis of dark current in IR detectors on thinned p-type HgCdTe

A model for the diffusion dark current in MIS IR detectors on thinned bulk p-type HgCdTe is discussed. The model includes trap-assisted tunneling mechanisms in the back-side depletion region as well as the effects of fast surface states. Expressions for the net recombination rate are developed for situations in which trap-assisted tunneling transitions are allowed. Calculations for 12-μm optical cutoff detectors operating at liquid-nitrogen temperature show that the properties of the back side, including surface fixed charge density, depletion region trap density, fast surface-state density, and majority carrier concentration, have a strong influence on the dark current levels of detectors on thin material. It is predicted that typical as-fabricated surface parameters will not result in large dark current densities. Calculations for detectors with surface parameters common to stressed (degraded) back surfaces, however, show dark current densities which would significantly affect detector performance     

带间共振隧穿二极管(RITD)

带间共振隧穿二极管(RITD)是导带与价带间发生共振隧穿的两端器件,其特点是启始电压VT和峰值电压Vp较低,电流峰谷比PVCR较大。在导出RITD物理模型和其电流密度方程的基础上重点介绍了InAs/AlSb/GaSbⅡ类异质结RITD、n+InAlAs/InGaAs/InAlAs/In-GaAs/p+InAlAsp-n结双势阱Ⅰ类RITD以及δ掺杂RITD三种RITD的器件结构、材料结构、工作原理、器件特性和参数等,并对这三种RITD的特点进行了比较和讨论。     

MEMS隧道加速度计的系统分析与设计

主要论述了一种新型体硅工艺MEMS隧道加速度计的系统分析与设计 ,对加速度计敏感头与伺服反馈电路组成的系统进行系统建模 ,其中包含了结构的模型和反馈控制电路的模型。以系统模型作为基础 ,分析了器件工作所必须的条件 ,对器件的结构参数和反馈控制电路的参数进行了设计 ,并给出了系统的静态与动态输出。另外 ,本文提出了参数敏感度因子的概念及其计算方法 ,利用这种方法可以对每一个参数计算其对应的敏感因子 ,从而为参数容差设计提供了依据