The effects of interface morphology on Schottky barrier heights: a case study on Al/GaAs(001)

TL;DR

This study uses first-principles calculations to investigate how interface morphology influences Schottky barrier heights at Al/GaAs contacts, revealing that semiconductor interface structure significantly impacts barrier height, unlike metal side distortions.

Contribution

It provides a quantitative analysis showing the dominant role of semiconductor interface structure over metal distortions in determining Schottky barrier heights.

Findings

Barrier height is minimally affected by metal-side distortions.

Semiconductor interface structure strongly influences barrier height.

Interface dipoles from ionic charges explain the observed effects.

Abstract

The problem of Fermi-level pinning at semiconductor-metal contacts is readdressed starting from first-principles calculations for Al/GaAs. We give quantitative evidence that the Schottky barrier height is very little affected by any structural distortions on the metal side---including elongations of the metal-semiconductor bond (i.e. interface strain)---whereas it strongly depends on the interface structure on the semiconductor side. A rationale for these findings is given in terms of the interface dipole generated by the ionic effective charges.