Effects of Interface Roughness Scattering on Radio Frequency Performance of Silicon Nanowire Transistors

TL;DR

This paper investigates how atomistic interface roughness impacts the radio frequency performance of silicon nanowire transistors, revealing significant performance degradation at diameters below 3 nm due to electron reflection caused by surface irregularities.

Contribution

It provides a detailed statistical analysis of interface roughness scattering effects on RF performance using full-band quantum transport simulations.

Findings

Significant reduction in cut-off frequency below 3 nm diameter.

Interface roughness causes electron reflection and mode-mismatch.

Electron velocity and transconductance decrease due to surface roughness.

Abstract

The effects of an atomistic interface roughness in n-type silicon nanowire transistors (SiNWT) on the radio frequency performance are analyzed. Interface roughness scattering (IRS) is statistically investigated through a three dimensional full-band quantum transport simulation based on the sp3d5s?* tight-binding model. As the diameter of the SiNWT is scaled down below 3 nm, IRS causes a significant reduction of the cut-off frequency. The fluctuations of the conduction band edge due to the rough surface lead to a reflection of electrons through mode-mismatch. This effect reduces the velocity of electrons and hence the transconductance considerably causing a cut-off frequency reduction.