Effects of Random Discrete Impurities in Ultra-short MOSFET Using 3D Monte Carlo Simulation

Abstract

This paper presents theoretical investigation of electron transport in the channel of 50 nm MOSFET with discrete random dopant distribution. The work is based on three-dimensional device Monte Carlo simulation. A model of electron-ion interaction suitable for discrete dopants has been developed by carefully separating the long-range and short-range parts of Coulomb potential effects. This model is validated through mobility calculation in silicon resistors and applied to MOSFET simulation. Discrete dopant distributions are compared with the case of continuous doping in terms of drain current. The transport is analysed through profile and cartography of electron concentration, electron velocity and electron flux. The presence of impurity in the inversion layer is shown to strongly affect locally these quantities and then the drain current.