均匀、阶梯和线性掺杂漂移区SOI RESURF器件的统一击穿模型

提出了一个均匀、阶梯和线性掺杂漂移区SOI高压器件的统一击穿模型.基于分区求解二维Poisson方程,得到了不同漂移区杂质分布的横向电场和击穿电压的统一解析表达式.借此模型并对阶梯数从0到无穷时器件结构参数对临界电场和击穿电压的影响进行了深入研究.从理论上揭示了在厚膜SOI器件中用阶梯掺杂取代线性漂移区,不但可以保持较高的耐压,而且降低了设计和工艺难度.解析结果、MEDICI仿真结果和实验结果符合良好.     

SOI RESURF器件高压互连线效应的二维解析模型

高压互连线效应是影响集成功率器件性能的重要因素之一。首先提出一个高压互连线效应对SOI横向高压器件的漂移区电势和电场分布影响的二维解析模型,进而得到漂移区在不完全耗尽和完全耗尽情况下的器件击穿电压解析表达式,而后利用所建立的模型,研究器件结构参数对击穿特性的影响规律,定量揭示在高压互连线作用下器件击穿多生在阳极PN结的物理本质,指出通过优化场氧厚度可以弱化高压互连线对器件击穿的负面影响,并给出用于指导设计的理论公式。模型的正确性通过半导体二维器件仿真软件MEDICI进行了验证。     

RESURF LDMOS功率器件表面场分布和击穿电压的解析模型

提出了RESURF LDMOS功率器件的表面电场分布和击穿电压的解析模型.根据二维泊松方程的求解,得到了与器件参数和偏压相关的表面电场和电势分布解析表达式.在此基础上,推出了为获得击穿电压和比导通电阻最好折中的优化条件.该解析结果与半导体器件数值分析工具MEDICI得到的数值分析结果和先前的实验数据基本一致,证明了解析模型的适用性.     

RESURF LDMOS功率器件表面场分布和击穿电压的解析模型

提出了 RESURF L DMOS功率器件的表面电场分布和击穿电压的解析模型 .根据二维泊松方程的求解 ,得到了与器件参数和偏压相关的表面电场和电势分布解析表达式 .在此基础上 ,推出了为获得击穿电压和比导通电阻最好折中的优化条件 .该解析结果与半导体器件数值分析工具 MEDICI得到的数值分析结果和先前的实验数据基本一致 ,证明了解析模型的适用性     

表面栅静电感应晶体管沿沟道中心线电势分布的解析分析

本文从表面栅静电感应晶体管(SIT)的基本物理模型出发,求出了沿沟道中心线的电势分布和沟道势垒高度的解析表达式.根据所得表达式具体计算了一个典型器件在不同栅源电压V_(GS)和漏源电压V_(DS)下的电势分布和势垒高度.其结果与1978年J.L.Morenza等人对同一器件用计算机数值分析所得的结果吻合较好. 本文给出了该种器件中势垒存在的物理模型,指出了表面栅与隐埋栅器件在势垒形成上的差别:表面栅器件中势垒的形成与源沟n~+n结有关;而隐埋栅器件势垒的形成与源沟n~+n结无关. 本文所得的解析表达式也表明,表面栅结构中势垒的出现需要沟道夹断一定的深度.这与1980年日本J.Ohmi用计算机数值分析所得结论是一致的. 本文所得的势垒高度的解析表达式可以作为进一步求解该种器件各电参数的解析表达式的基础.     

TFSOI RESURF功率器件表面电场分布和优化设计的新解析模型

提出了 TFSOI RESURF功率器件的表面电场分布和优化设计的新解析模型 .根据二维泊松方程的求解 ,得到了表面电场和电势分布的相关解析表达式 .在此基础上 ,推出了为获得最大击穿电压的优化条件。讨论了击穿电压和漂移区长度及临界掺杂浓度和场氧化层、埋氧化层的关系 .解析结果与半导体器件数值分析工具 DESSISE-ISE得到的数值分析基本一致 ,证明了新解析模型的适用性 .     

内调制光电探测器特性的模拟与实验分析

给出了内调制光电探测器受光结光生电压、输出结电流及内调制特性的理论模型;在此基础上进行数值计算,得到模拟曲线;并将实验曲线与模拟曲线对比,结果吻合.然后深入分析了栅压对受光结的光电特性的影响,以及在横向发生的抽取效应对受光结的影响,并对此器件内调制特性进行解析,阐明了其内调制工作机制.     

TFSOI RESURF功率器件表面电场分布和优化设计的新解析模型

提出了TFSOI RESURF功率器件的表面电场分布和优化设计的新解析模型．根据二维泊松方程的求解,得到了表面电场和电势分布的相关解析表达式．在此基础上,推出了为获得最大击穿电压的优化条件。讨论了击穿电压和漂移区长度及临界掺杂浓度和场氧化层、埋氧化层的关系．解析结果与半导体器件数值分析工具DESSISE-ISE得到的数值分析基本一致,证明了新解析模型的适用性．     

一维PSD的光电性能解析研究

位置敏感探测器（ＰＳＤ）是一种基于横向光电效应的光敏器件,本文从描述横向光电效应的Ｌｕｃｏｖｓｋｙ方程出发,分析了几种不同情况下一维ＰＳＤ输出信号的解析解,讨论了一维ＰＳＤ的响应特性、线性条件及位置公式。     

一种新型的晶闸管结构—MOS栅控横向晶闸管

本文提出了一种新型的晶闸管器件结构,它是由MOS型和双极型复合构成的MOS栅控横向晶闸管,其输入阻抗高,电压控制,用低压就能控制大功率输出.     

MEMS magnetic field sensor based on silicon bridge structure

A MEMS piezoresistive magnetic field sensor based on a silicon bridge structure has been simulated and tested.The sensor consists of a silicon sensitivity diaphragm embedded with a piezoresistive Wheatstone bridge,and a ferromagnetic magnet adhered to the sensitivity diaphragm.When the sensor is subjected to an external magnetic field, the magnetic force bends the silicon sensitivity diaphragm,producing stress and resistors change of the Wheatstone bridge and the output voltage of the sensor.Good agreeme...     

Ge1−xSnx stressors for strained-Ge CMOS

A strong piezoresistive effect of GaAs micro-structure which is based on high electron mobility transistor (HEMT) is reported in this paper. The GaAs HEMT is embedded in the root of the cantilever as the sensitive element in order to detect the deformation. The strain is simulated with the ANSYS software, and the maximum gauge factor is about 26,350, which is nearly a hundred times larger than that of piezoresistive silicon. The high gauge factor is not only due to the option of voltage bias, but also the combination of the piezoresistive and piezoelectric effect. The obtained results demonstrate that GaAs micro-structure based on HEMT can be suitable for high sensitive stress/pressure sensors.     

叠加电桥检测的加速度传感器的设计

This paper describes the design,simulation,processing and test result of a high sensitivity accelerometer based on the piezoresistive effect which uses an overlay bridge detection method.The structure of this accelerometer is supersymmetric "mass-beams".This accelerometer has 8 beams,where two varistors are put in the two ends.Four varistors compose a Wheatstone bridge and the output voltages of the 4 Wheatstone bridges have been superimposed as the final output voltage.The sensitivity of the accelerometer can be improved effectively by these clever methods. A simplified mathematical model has been created to analyze the mechanical properties of the sensor,then the finite element modeling and simulation have been used to verify the feasibility of the accelerometer.The results show that the sensitivity of the accelerometer is 1.1381 m V/g,which is about four times larger than that of the single bridge accelerometers and series bridge sensor.The bandwidth is 0-1000 Hz which is equal to that of the single bridge accelerometers and the series bridge sensor.The comparison reveals that the new overlay detection bridge method can improve the sensitivity of the sensor in the same bandwidth.Meanwhile,this method provides an effective method to improve the sensitivity of piezoresistive sensors.     

A monolithic capacitive pressure sensor with pulse-period output

A new microminiature monolithic capacitive pressure transducer (CPT I) is 20 times more sensitive than piezoresistive strain-gauge pressure transducers, requires one percent of the power, and can be batch fabricated through current integrated circuit technology. A second device (CPT II) incorporates bipolar signal-processing electronics on the same silicon chip to produce a low-duty-cycle pulse-mode output with period related to pressure. This output format helps to re-solve the problem of shunting between leads, which is one of the principal causes of long-term drift in piezoresistive transducers designed for implantable medical applications. Because this device uses capacitance change as a transductional mechanism rather than piezo-resistivity, it is not susceptible to drift caused by temperature variations in the piezoresistive coefficient. Optimization for totally implantable biomedical applications places special emphasis on small size, high sensitivity, improved long-term baseline stability, and greatly reduced power consumption. These properties are also important for a wide range of pressure-sensing applications-from automotive to general industrial use.     

Analysis of the Instantaneous Power Flow for Three-Phase PWM Boost Rectifier Under Unbalanced Supply Voltage Conditions

This paper proposes the analysis of the instantaneous power flow of three-phase pulse-width modulation (PWM) boost rectifier under unbalanced supply voltage conditions. An analytical expression for the instantaneous output power has been derived, which provides the link between the output dc link voltage and the instantaneous output power. A direct relationship between the dc link voltage ripples and the second harmonic component in the instantaneous output power has been established. Based on the input and output instantaneous power analytical expressions provided, the presence of the odd order harmonic components in the ac line currents can be explained. A simple cascaded PI control scheme has been developed for the dc output voltage control. The controller ensures that the dc link voltage is maintained constant and the supply side power factor is kept close to unity under the unbalanced supply voltage operating conditions. Simulation and experimental test results are provided on a 1.6-kVA laboratory-based PWM rectifier to validate the proposed analysis and control scheme.      

DC-Voltage-Ratio Control Strategy for Multilevel Cascaded Converters Fed With a Single DC Source

Recently, a multilevel cascaded converter fed with a single dc source has been presented. An analysis of the steady-state working limits of this type of converter is presented in this paper. Limits of the maximum output voltage and the minimum and maximum loading conditions for stable operation of the converter are addressed. In this paper, a way to achieve any dc voltage ratio (inside the stable operation area of the converter) between the H-bridges of the single-dc-source cascaded H-bridge converter is presented. The proposed dc-voltage-ratio control is based on a time-domain modulation strategy that avoids the use of inappropriate states to achieve the dc-voltage-ratio control. The proposed technique is a feedforward-modulation technique which takes into account the actual dc voltage of each H-bridge of the converter, leading to output waveforms with low distortion. In this way, the dc voltage of the floating H-bridge can be controlled while the output voltage has low distortion independently of the desired dc voltage ratio. Experimental results from a two-cell cascaded converter are presented in order to validate the proposed dc-voltage-ratio control strategy and the introduced concepts.      

基于恒流源的改进型压电陶瓷高压驱动电源

恒流源压电陶瓷驱动电源具有结构简单及频响好等优点,但静态功耗高是其突出缺点。该文提出了一种改进的恒流源压电陶瓷驱动电源,在静态功耗一定的情况下,提高了其动态输出能力及竞争能力。该改进型压电陶瓷驱动电源的样机具有2.4~300V的输出电压范围,在静态恒定电流为0.1A时,动态输出电流最大可达0.44A。基于恒流源的高压驱动电源,驱动电压主要由驱动管的耐压决定,原理上可得到远高于现有高压运放的水平,在高压压电陶瓷驱动方面有广阔的前景。     

Characterization of highly doped n- and p-type 6H-SiCpiezoresistors

Highly doped (~2×10¹⁹ cm^-3) n- and p-type 6H-SiC strain sensing mesa resistors configured in Wheatstone bridge integrated beam transducers were investigated to characterize the piezoresistive and electrical properties. Longitudinal and transverse gauge factors, temperature dependence of resistance, gauge factor (GF), and bridge output voltage were evaluated. For the n-type net doping level of 2×10¹⁹ cm^-3 the bridge gauge factor was found to be 15 at room temperature and 8 at 250°C. For this doping level, a TCR of -0.24%/°C and -0.74%/°C at 100°C was obtained for the n- and p-type, respectively. At 250°C, the TCR was -0.14%/°C and -0.34%/°C, respectively. In both types, for the given doping level, impurity scattering is implied to be the dominant scattering mechanism. The results from this investigation further strengthen the viability of 6H-SiC as a piezoresistive pressure sensor for high-temperature applications     

Piezoresistive effect in GaAs/InxGa1−xAs/AlAs resonant tunneling diodes for application in micromechanical sensors

The current–voltage characteristics of GaAs/In_xGa_1−xAs/AlAs resonant tunneling diodes (RTDs) are a function of stress, and the current–voltage changes of RTDs with stress are attributed to the piezoresistive effect in RTDs. In order to study the piezoresistive effect in RTDs for application in micromachined mechanical sensors, the beam-mass structure based on RTDs is designed, fabricated and tested by the Wheatstone bridge test circuit. The test results show that the piezoresistive sensitivity of RTDs can be adjusted through the bias voltage, and the maximal piezoresistive sensitivity of RTDs with bias voltage at 0.618 V is 7.61×10⁻¹¹ Pa⁻¹, which is two orders higher than the minimal piezoresistive sensitivity (2.03×10⁻¹³ Pa⁻¹) of RTDs with bias voltage at 0.656 V, and is also higher than the piezoresistive sensitivity of silicon material (5.52×10⁻¹¹ Pa⁻¹).     

基于共振隧穿二极管的应力检测方法

共振隧穿二极管(RTD)具有微分负阻效应,且其共振隧穿的I-V特性随着廊力的变化而变化,这就是RTD的压阻效应.与半导体材料压阻效应的应用类似,RTD也可用于应力检测.文中研究了两种基于RTD的应力检测方法.在讨论频率-应力检测法的基础上提出了一种新颖的应力检测方法--惠斯通RTD电桥检测法.测试结果表明,基于惠斯通RTD电桥检测法得到的压阻灵敏度随偏置电压可调,町调范围达到三个数量级.