Atomic ordering in self-assembled Ge:Si(001) islands observed by X-ray scattering

TL;DR

This study uses X-ray scattering to reveal atomic ordering and antiphase boundaries in self-assembled Ge:Si(001) islands and wetting layers, providing insights into their internal structure and composition.

Contribution

It demonstrates the presence of atomic ordering and antiphase boundaries in Ge:Si islands using X-ray scattering, a novel application for understanding their internal structure.

Findings

Evidence of atomically ordered SiGe domains in islands and wetting layer

Detection of antiphase boundaries in ordered domains

Modeling of X-ray profiles elucidates domain structures

Abstract

X-ray diffuse scattering in the vicinity of a basis-forbidden (200) Bragg reflection was measured for a sample with uncapped self-assembled Ge islands epitaxially grown on Si(001). Our results provide evidence of atomically ordered SiGe domains in both islands and wetting layer. The modeling of x-ray profiles reveals the presence of antiphase boundaries separating the ordered domains in a limited region of the islands where the stoichiometry is close to Si0.5Ge0.5.