Atomically Controlled Epitaxial Growth of Single-Crystalline Germanium Films on a Metallic Silicide

TL;DR

This paper presents a method for growing high-quality, atomically controlled germanium films on metallic silicide substrates using molecular beam epitaxy, enabling potential advancements in Ge-channel transistors.

Contribution

It introduces a novel epitaxial growth technique for germanium on Fe3Si with atomic-level control, improving film quality and strain management.

Findings

High-quality Ge films grown on Si-terminated Fe3Si(111) surface.

Controlled 2D and 3D Ge growth modes via surface termination.

Potential application in vertical Ge-channel transistors.

Abstract

We demonstrate high-quality epitaxial germanium (Ge) films on a metallic silicide, Fe3Si, grown directly on a Ge(111) substrate. Using molecular beam epitaxy techniques, we can obtain an artificially controlled arrangement of silicon (Si) or iron (Fe) atoms at the surface on Fe3Si(111). The Si-terminated Fe3Si(111) surface enables us to grow two-dimensional epitaxial Ge films, whereas the Fe-terminated one causes the three-dimensional epitaxial growth of Ge films. The high-quality Ge grown on the Si-terminated surface has almost no strain, meaning that the Ge films are not grown on the low-temperature-grown Si buffer layer but on the lattice matched metallic Fe3Si. This study will open a new way for vertical-type Ge-channel transistors with metallic source/drain contacts.