Quantum mechanical simulation of current noise of nanoscale double-gate MOSFETs

点击翻译按钮获取中文摘要

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. 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 various shape of electrodes are injected into the inversion layer of the channel and confined to quantized subbands as the so-called two-dimensional electron gases. It is found from the NEGF simulation that the drain current noise is always suppressed below the full Pois … More sonian value partly due to the Fermi correlation and partly due to the partition noise of electrons injected from the electrodes. Further, the current noise to average current ratio (Fano-factor) is found to be suppressed strongly with the increase of gate bias and the decrease of operating temperature.2. 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 double-gate Si-MOSFET. The quantum mechanical effects are incorporated in terms of a quantum correction of potential in this particle model. It is shown that the incorporation of the ellipsoidal multi-valleys of silicon conduction band and energy quantization effects are important to analyze the current noise in ultra small Si-MOSFETs. As a result, it is found that the fractional deviation of current noise never increase s but decreases a little even if the channel length is reduced to less than a few ten nanometers. Less