共查询到19条相似文献,搜索用时 125 毫秒
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Amit Chaudhry 《微纳电子技术》2011,48(6):357-364
研发了一种通过MOSFET的超薄栅氧化物分析直接隧穿电流密度的模型。采用Wentzel-Kramers-Brilliouin(WKB)近似计算了隧穿概率,利用清晰的表面势方程改进模型的准确性。在研究模型中考虑了Si衬底中反型层的量子化和多晶硅栅耗尽,还研究了多晶硅掺杂对栅氧化层隧穿电流的影响。仿真结果表明,栅氧化层隧穿电流随多晶硅栅掺杂浓度的增加而增加。该结论与已报道的结果相吻合,从而证明了该模型的正确性。 相似文献
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首先介绍了共振隧穿理论和一种新效应--介观压阻效应,对AlxGa1-xAs/GaAl/AlxGa1-xAs共振隧穿双势垒结构的轴向施加压应变作了分析,然后计算了轴向应变对垒宽和垒高的影响,对透射系数和隧穿电流用Matlab作了仿真.发现压应变可以使隧穿电流线性增加,偏压不同电流增加的速率也不同,为设计共振隧穿器件提供了理论依据. 相似文献
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基于一种非局域化的输运模型,对不同结构不同温度下的中红外量子级联激光器的输运特性进行了仿真。在这个模型中,利用量子隧穿、微带隧穿以及热载流子输运等长程载流子输运模型,对传统的扩散-漂移方程进行了矫正.并将基于上述集成模型的计算结果和实验结果进行了比较,通过拟合参数的合理设置,计算结果和实验结果得到了很好的吻合. 相似文献
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增大传感器振子的质量和静态测试电容可以减小电容式MEMS惯性传感系统的噪声,而深度粒子反应刻蚀工艺由于复杂的工艺原因,当深宽比较大时,不能刻蚀出大质量和大初始电容的传感器.据此,本文研究了一种磁驱动增大检测电容的MEMS惯性传感器,通过电磁驱动器,传感器的静态测试电容可以大幅增加,在梳齿电容上刻蚀阻尼槽后,其机械噪声达到0.61μg每根号赫兹,仿真其共振频率为598Hz,静态位移灵敏度为0.7μm每重力加速度,基于硅 玻璃键合工艺,制作了栅形条电容式惯性传感器,并用电磁驱动的方式测试其品质因子达到715,从而验证了制作工艺的可行性和电磁驱动器改变传感器初始静态测试电容的可行性. 相似文献
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《Microelectronics Reliability》2014,54(6-7):1192-1199
In this paper, we propose a multiphysics-based optimization of the geometry of a microbeam, which represents the sensing part of a Lorentz force, resonating, MEMS magnetometer. The optimization problem is framed by accounting for a (weak) electro-thermo-mechanical coupling, which induces a state of residual stresses in the microbeam, clamped at both its ends. Nonlinearities caused by the aforementioned residual stresses and by the electrostatic sensing are taken into account up to second order. In the optimization procedure, two objective functions are handled, as linked to the sensitivity (to be maximized) and to the power consumption (to be minimized) of the system; a constraint is also accounted for to ensure the sensor to work within a required frequency regime.By considering the microbeam width and length as design parameters, we show that a set of possible optimal designs can be obtained by tuning the weighting factors mixing the two aforementioned objective functions. 相似文献
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现普遍采用的轮轨力测试方法一般是测力轮对法或根据我国规范测试轮轨力方法较为常用。测力轮对法虽然可以实现轮轨力在线连续测量,但需要安装专门的轮对,不便于现场普遍测试。按照测试规范进行测试又不能实现地面轮轨力连续测量。中国铁路交通具有运量大、车次频、速度越来越快等显著特征,在这样的背景下,研究出地面连续测量轮轨垂向力的方法对于保证列车运行安全具有普遍作用。从轨道结构力学方法入手,结合有限元结构计算,研究轨道结构受力形态和轨枕支承反力分布情况,进而研究地面连续测量轮轨垂向力的方法。 相似文献
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Investigation of a Lorentz force biomagnetometer 总被引:3,自引:0,他引:3
This work evaluates an approach to the noninvasive measurement of small ionic current flows by a technique of Lorentz force magnetometry. An instrument was constructed that is basically a very sensitive force-balance that can measure Lorentz forces experienced by ionic currents flowing in small objects when exposed to strong oscillating magnetic fields. For objects that can fit on a microscope slide, the system is sensitive to ion current dipole moments as low as 180 pA-m. Images were made of ionic currents flowing in thin profiles by a process of scanning a localized magnetic field over the object, measuring generated Lorentz forces, and using a computer to reconstruct images. It can be shown that this method of Lorentz magnetometry has an immunity to ambient magnetic noise and has system characteristics that might suggest its possible use in biomagnetometry of small thin specimens 相似文献
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The motion of a charged particle in time-varying uniform electric and magnetic fields has been determined exactly by writing the Lorentz force equation in a matrix form. The general solution is obtained by solving the ordinary first-order linear differential equation. 相似文献
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This paper addresses MEMS testing through a case study: a micromachined magnetic field sensor with on-chip electronics. The sensor element is based on a cantilever beam that is deflected by means of the Lorentz force. Embedded piezoresistors are used to detect strain in the cantilever beam and thus to detect the magnetic field. A test approach is presented for the whole system focussing on fault classification, on design for testability and on production test costs. Fault classification introduces several catastrophic and parametric faults on both mechanical and electrical elements. Simple and low-cost design for testability such as test point insertion is then discussed for test cost reduction and for fault coverage enhancement. 相似文献
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A small, low-cost, highly sensitive system to record geomagnetic fluctuations on the ocean floor is described. The technique employed is to amplify the effective sensitivity of the Cs-vapor magnetometer with an intermediate stage discriminator amplifier voltagecontrolled oscillator prior to magnetic recording. The resultant overall electronic system noise level obtained is well below the inherent noise level of the sensor, permitting accurate measurement of undersea magnetic fluctuations up to 5 Hz. 相似文献