Transient-Enhanced Surface Diffusion on Native-Oxide-Covered Si(001) Nano-Structures during Vacuum Annealing

TL;DR

This study investigates how native oxide layers on Si(001) surfaces significantly enhance surface diffusion during low-temperature vacuum annealing, leading to shape changes that cease once the oxide desorbs.

Contribution

It reveals the transient nature of surface diffusion enhancement caused by native oxide during annealing, highlighting the role of native oxide in surface mass transport.

Findings

Enhanced surface diffusion occurs only with native oxide present.

Surface shape transformation is transient and ceases after oxide desorption.

No enhancement observed on HF-etched, oxide-free surfaces.

Abstract

We report on the transient-enhanced shape transformation of nano-structured Si(001) surfaces upon in vacuo annealing at relatively low temperatures of 1175K - 1225K for a few minutes. We find dramatic surface mass transport concomitant with the development of low-energy facets on surfaces that are covered by native oxide. The enhanced surface mass transport ceases after the oxide is completely desorbed, and it is also not observed on surfaces where the native oxide had been removed by HF before annealing.