Molecular-beam epitaxy of GaSb on 6{\textdegree}-offcut (001) Si using a GaAs nucleation layer

TL;DR

This study demonstrates optimized molecular beam epitaxy of high-quality GaSb layers on offcut silicon substrates using a GaAs nucleation layer, revealing detailed growth mechanisms and improved layer quality over traditional methods.

Contribution

It introduces a novel growth process for GaSb on Si with a GaAs nucleation layer, providing insights into growth stages and layer relaxation behaviors.

Findings

Formation of high-density GaAs islands during initial growth

GaSb nucleates as 3D islands then transitions to 2D growth

GaSb layer quality surpasses that of layers grown with AlSb nucleation layers

Abstract

We studied and optimized the molecular beam epitaxy of GaSb layers on vicinal (001) Si substrates using a GaAs nucleation layer. An in-depth analysis of the different growth stages under optimized conditions revealed the formation of a high density of small GaAs islands forming a quasi-two-dimensional layer. GaSb then nucleated atop this layer as three-dimensional islands before turning to two-dimensional growth within a few nanometers. Moreover, reflexion high-energy electron diffraction revealed a fast relaxation of GaAs on Si and of GaSb on GaAs. The GaSb layer quality was better than that of similar layers grown on Si through AlSb nucleation layers.