Research of current fluctuations of nanoscaled MOSFETs based upon quantum transport models

本研究采用基于非平衡绿色函数模型（NEGF）的量子输运模型和量子修正的蒙特卡罗（MC）器件模拟方法，研究了纳米MOS器件的电流噪声特性。1.量子修正的蒙特卡罗模型量子修正的MC模型已经发展到能够模拟常温下实际半导体器件的水平，并将其应用于纳米Si-MOSFET的电流波动研究。在这个粒子模型中的量子力学效应被纳入在量子修正的潜力。在输运模拟中还考虑了硅导带的椭球多谷现象，这在纳米器件的实际模拟中具有重要意义。我们已经发现，在纳米尺度MOSFET中的沟道电子的数量的减少导致在电子电流的大的时间波动。当器件的沟道长度变为s时， ...更多信息 纳米尺度越小，电子的渡越时间越短，由于电子平均能量的增加，电子的散射时间也越短，2.非平衡绿色函数模型利用非平衡格林函数模型（NEGF）研究了电子的量子力学关联对散粒噪声的抑制作用。半导体纳米级器件，从而讨论了低温下的电流噪声。将NEGF模型应用于弹道纳米Si-MOSFET的散粒噪声研究是一个有趣的研究方向。当电极中的三维电子被注入反型层并被限制在量子化的子带中时，即所谓的二维电子气中，预计电子之间存在相关性。反型层中的量子化和相位相干输运预计会影响弹道纳米Si-MOSFET的噪声性能。然而，到目前为止，我们还没有观察到散粒噪声抑制在纳米MOSFET的模拟。少

In this research project, we have studied the current noise characteristics of nano-scale MOS devices by employing the quantum transport models based upon the nonequilibrium Green's function model (NEGF) and the quantum corrected Monte Carlo (MC) device simulation.1.Quantum corrected Monte Carlo modelThe quantum corrected MC model has been developed to simulate practical semiconductor devices at normal temperatures, and applied to the study of the current fluctuations of a nano-scale Si-MOSFET. The quantum mechanical effects are incorporated in terms of a quantum correction of potential in this particle model. The ellipsoidal multi-valleys of silicon conduction band are also considered in the transport simulation, which is very important in the practical simulation of nano-scaled devices. We have found that the decrease in the number of channel electrons in nano-scale MOSFETs lead to large temporal fluctuations in the electronic current. When the channel length of the devices becomes s … More horter in nano-scale, the transit time of electrons becomes shorter, and the scattering time of electrons also becomes shorter due to the increase of the average energy of electrons, which makes the autocorrelation time of the drain current shorter and consequenrly temporal fluctuations larger.2.Nonequilibrium Green's function modelThe NEGF is used to study the shot noise suppression caused by the quantum mechanical correlations of electrons in semiconductor nano-scale devices, so that the current noise is discussed at low temperature. It was considered interesting to apply the NEGF models to the study of shot noise in ballistic nano-scale Si-MOSFETs, where correlations of electrons are expected to exist when the three dimensional electrons in the electrodes are injected into the inversion layer and confined to quantized subbands as the so-called two-dimentional electron gases. Quantization in the inversion layer and phase coherent transport were anticipated to influence noise performance in ballistic nanoscale Si-MOSFETs. However, up to now, we have not yet observed the shot noise suppression in the simulation of nanoscale MOSFETs. Less