共查询到20条相似文献,搜索用时 171 毫秒
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采用自洽解方法求解一维薛定谔方程和二维泊松方程,得到电子的量子化能级和相应的浓度分布,利用MWKB方法计算电子隧穿几率,从而得到不同栅偏置下超薄栅介质MOSFET的直接隧穿电流模型。一维模拟结果与实验数据十分吻合,表明了模型的准确性和实用性。二维模拟结果表明,低栅压下,沟道边缘隧穿电流远大于沟道中心隧穿电流,沟道各处的隧穿电流均大于一维模拟结果;高栅压下,隧穿电流在沟道的分布趋于一致,且逼近一维模拟结果。 相似文献
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利用FN电流估计薄栅MOS结构栅氧化层的势垒转变区的宽度 总被引:2,自引:2,他引:0
通过数值求解整个势垒的薛定谔方程 ,发现 FN电流公式中的 B因子强烈依赖势垒的转变区的宽度 ,而 C因子则弱依赖于势垒的转变区的宽度 .给出了一种利用 WKB近似所得的处理电子隧穿存在转变区势垒的过程 ,并得到一个 FN电流的分析表达式 .它可用来估计薄栅 MOS结构的栅氧化层的势垒转变区的宽度 .在转变区的宽度小于 1nm时 ,它与数值求解薛定谔方程的结果吻合得很好 ,表明该方法可以用来估计势垒转变区的宽度 .实验的结果表明 B因子随温度有较大的变化 ,这个结果验证了该方法的部分预测结果 相似文献
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基于Slonczewski理论模型和矩阵方法研究了由栅控制中间层电势高度的磁性隧道结的隧穿磁阻效应。数值计算了中间层势垒为0~3 V以及中间层势阱为0~3 V的磁性隧道结的隧穿磁阻随着中间层厚度改变的变化曲线。计算结果表明,当中间层为势垒时,隧穿磁阻随着中间层厚度单调下降;当中间层为势阱时,隧穿磁阻随着中间层厚度振荡,并且相比于势垒情况时明显提高。这说明栅控中间层磁性隧道结相比于传统磁性隧道结具有更好的可控性和提高隧穿磁阻效应的潜力。 相似文献
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已研制成了肖特基栅共振隧穿晶体管,在双势垒结构上蒸发铂金形成栅。通过调制准二维电子积累层的面积进而达到控制隧穿电流的目的。并对发射极正反接电压不同而出现的不同调制现象进行了分析。 相似文献
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A method of computing potential distribution, electron trajectories and deflection parameters of the travelling-wave deflection
system is introduced. An approximate expression of potential distribution is obtained. The results of computation agree well
with measured values, showing that this method is suitable for engineering design. 相似文献
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本文提出了计算慢波偏转系统中电位分布、电子轨迹、偏转参量的方法。电位分布在数值计算的基础上,以解析表达式近似。计算结果与实际管子的特性很好地吻合,表明本方法适用于工程设计。 相似文献
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《Electron Devices, IEEE Transactions on》1960,7(4):195-205
In a conventional Pierce-type gun, the anode aperture causes a potential reduction in the cathode-anode region from the ideal Langmuir potential distribution. For low-voltage gating of the electron beam, a mesh grid of spherical shape (conforming to an equipotential surface) is used in front of the cathode. When this grid is operated at the Langmuir potential depicted by its relative position, there is a difference in the potential gradients on its two sides. This difference causes a lens action at each mesh element which results in a displacement of the actual electron trajectory from the ideal laminar trajectory in the region beyond the anode. A means for calculating these displacements as a function of distance along the axis is developed. As the grid lenses are divergent, the images of the mesh elements in any plane beyond the anode are larger than those for ideal laminar flow, resulting in a current density distribution which differs from that of the ideal beam. A means of calculating the current density profile by summing the effects of the grid lenses is devised, and the method is applied to a sample gun design to illustrate the effect on the current density distribution. 相似文献
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多级降压收集极被广泛地应用于空间行波管的设计中,本文介绍了一种四级降压收集极的设计和模拟方法。通过对某一空间行波管互作用后的废电子注信息进行分析,得到电子注在收集极的入口条件,并且根据电子注入口条件确定各电极的电位,用行波管模拟软件模拟废电子注在收集极内的发射情况,计算出收集极的效率,通过分析电子注粒子运行轨迹和能量分布,优化收集极边界条件和各电极电位设置,提高收集极效率,降低电子回流率。结果表明:利用此方法计算得到的收集极效率达到80%以上,该模拟分析方法对行波管收集极的研究设计具有参考价值。 相似文献
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The kinetic equation for the electron distribution function in a one-dimensional semiconductor with a spatial-periodic potential in the presence of a weak pulling electric field was analytically solved in the limiting case of the infinite length of carrier energy relaxation. An explicit expression for the conductivity of the system was derived for a sinusoidal potential profile with an arbitrary amplitude. It was shown that the singularities in the electron distribution function, arising in the asymptotic limit, are smoothed in the region of finite lengths of energy relaxation. A comparison with the results of an opposite (local) mode shows that conductivity in the significantly nonlocal case is lower at any potential amplitude. 相似文献
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薛舫时 《固体电子学研究与进展》2002,22(1):32-37
运用依赖能量的异质界面δ散射势和多能谷有效质量方程计算了 Ga As/Al As异质结构中的能带混合和电子隧穿共振。结合能带混合隧穿共振理论和 Monte Carlo模拟计算 ,编制异质谷间转移电子器件的模拟软件。用该软件模拟了器件的直流伏安特性和射频工作。由模拟结果与测量结果的对比中确定出δ散射势参数和隧穿时间。通过模拟发现了新的弛豫振荡模式。研究了弛豫振荡模的各种振荡特性 ,给出了器件的优化设计 相似文献
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Hasnat K. Choh-Fei Yeap Jallepalli S. Hareland S.A. Shih W.-K. Agostinelli V.M. Tasch A.F. Maziar C.M. 《Electron Devices, IEEE Transactions on》1997,44(1):129-138
A thermionic emission model based on a non-Maxwellian electron energy distribution function for the electron gate current in NMOSFET's is described. The model uses hydrodynamic equations to describe more correctly the electron transport and gate injection phenomena in submicron devices. A generalized analytical function is used to describe the high-energy tail of the electron energy distribution function. Coefficients of this generalized function are determined by comparing simulated gate currents with the experimental data. This model also includes the self-consistent calculation of the tunneling component of the gate current by using the WKB approximation, and by using a more accurate representation of the oxide barrier by including the image potential. Good agreement with gate currents over a wide range of bias conditions for three different technological sets of devices are demonstrated by using a single set of coefficients 相似文献
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本文研究了电磁波泵浦的自由电子激光器。从跃变磁场结构出来的大半径迴旋环形电子束通过圆柱形波导与圆柱形波导的TE11模入射电磁波相作用。利用电子束的弗拉索夫分布函数理论和三维波导模的波动方程求得在康普顿区域中的散射波色散关系。通过数值分析,讨论了轴向引导磁场,电子束能量,电子迴旋比和电子束环的径向位置等与散射波频率和增长率的关系。 相似文献
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Computational formulae for the coefficients of the third-order spherical aberration and the second-order axial chromatic aberration are presented for an axially symmetric electrostatic electron mirror. A technique for eliminating the high-order derivatives of the potential axial distribution in mirror systems from the integrands is described. Conditions for elimination of spherical and axial chromatic aberrations, either separately or simultaneously, are found for a three-electrode axially symmetric mirror composed of coaxial cylinders of the same diameter. A principal scheme of the transmission electron microscope, where an electrostatic electron mirror serves as its objective, is presented. 相似文献