A unified treatment of current-induced instabilities on Si surfaces

TL;DR

This paper presents a unified model explaining current-induced surface instabilities on silicon, linking diffusion differences near steps to step bunching and wandering phenomena observed experimentally.

Contribution

It introduces a two-region diffusion model that maps onto the sharp-step model, providing a unified interpretation of surface instabilities on Si surfaces.

Findings

Negative kinetic coefficients relate to faster diffusion near steps.

The model explains experimental step bunching and wandering.

Unified interpretation applies to Si(111) and Si(001) surfaces.

Abstract

We introduce a simple two region model where the diffusion constant in a small region around each step on a vicinal surface can differ from that found on the terraces. Steady state results for this model provide a physically suggestive mapping onto kinetic coefficients in the conventional sharp-step model, with a negative coefficient arising from faster diffusion in the step region. A linear stability analysis of the resulting sharp-step model provides a unified and simple interpretation of many experimental results for current-induced step bunching and wandering instabilities on both Si(111) and Si(001) surfaces.