Performance Evaluation of Ballistic Silicon Nanowire Transistors with Atomic-basis Dispersion Relations

TL;DR

This study evaluates the bandstructure effects on silicon nanowire transistors using tight binding models, revealing how quantum confinement influences their ballistic current and carrier velocity, with implications for device performance limits.

Contribution

It introduces an atomic-basis dispersion relation approach to analyze ballistic silicon nanowire transistors, providing new insights into their current and velocity characteristics.

Findings

Ballistic p-SNWTs deliver half the ON-current of n-SNWTs at large diameters.

At small diameters, p- and n-SNWTs have similar ON-currents.

Quantum confinement significantly impacts SNWT performance limits.

Abstract

In this letter, we explore the bandstructure effects on the performance of ballistic silicon nanowire transistors (SNWTs). The energy dispersion relations for silicon nanowires are evaluated with an sp3d5s* tight binding model. Based on the calculated dispersion relations, the ballistic currents for both n-type and p-type SNWTs are evaluated by using a semi-numerical ballistic model. For large diameter nanowires, we find that the ballistic p-SNWT delivers half the ON-current of a ballistic n-SNWT. For small diameters, however, the ON-current of the p-type SNWT approaches that of its n-type counterpart. Finally, the carrier injection velocity for SNWTs is compared with those for planar metal-oxide-semiconductor field-effect transistors, clearly demonstrating the impact of quantum confinement on the performance limits of SNWTs.