Sculpting the shape of semiconductor heteroepitaxial islands: from dots to rods

TL;DR

This paper demonstrates how metal patterns influence the shape and structure of Ge islands on Si, enabling precise control over their morphology from dots to rods through metal-mediated growth mechanisms.

Contribution

It reveals the role of metal species and substrate orientation in shaping heteroepitaxial islands and highlights the importance of Si-Ge intermixing in their evolution.

Findings

Metal patterns control island shape and facet orientation.

Metal promotes growth of specific facets.

Si-Ge intermixing influences island evolution.

Abstract

In the Ge on Si model heteroepitaxial system, metal patterns on the silicon surface provide unprecedented control over the morphology of highly ordered Ge islands. Island shape including nanorods and truncated pyramids is set by the metal species and substrate orientation. Analysis of island faceting elucidates the prominent role of the metal in promoting growth of preferred facet orientations while investigations of island composition and structure reveal the importance of Si-Ge intermixing in island evolution. These effects reflect a remarkable combination of metal-mediated growth phenomena that may be exploited to tailor the functionality of island arrays in heteroepitaxial systems.