Effect of discrete impurities on electron transport in ultra-short MOSFET using 3D Monte Carlo simulation

TL;DR

This study uses 3D Monte Carlo simulations to analyze how discrete impurities in ultra-short MOSFETs affect electron transport and drive current, revealing significant sensitivity to impurity placement.

Contribution

It introduces a detailed electron-ion interaction model for discrete impurities in 3D Monte Carlo simulations of 50 nm MOSFETs, highlighting impurity position effects.

Findings

Drive current varies by 23% due to impurity position.

Single impurity placement significantly impacts transport properties.

Impurity effects influence threshold voltage and high drain voltage behavior.

Abstract

This paper discusses the influence of the channel impurity distribution on the transport and the drive current in short-gate MOSFET. In this purpose, a careful description of electron-ion interaction suitable for the case of discrete impurities has been implemented in a 3D particle Monte Carlo simulator. This transport model is applied to the investigation of 50 nm MOSFET operation. The results show that a small change in the number of doping impurities or in the position of a single discrete impurity in the inversion layer may significantly influence the drain current. This effect is not only related to threshold voltage fluctuations but also to variations in transport properties in the inversion layer, especially at high drain voltage. The results are analyzed in terms of local fluctuations of electron velocity and current density. In a set of fifteen simulated devices the drive current Ion, determined at VGS = VDS = 0.6 V, is found to vary in a range of 23% according to the position of channel impurities.