Ge condensation under SiGe oxidization: from Molecular Dynamics simulation to one-dimensional analytic modeling

TL;DR

This paper models the oxidation of SiGe alloys using molecular dynamics and develops a one-dimensional analytical model to describe germanium condensation during oxidation, revealing segregation behavior and strain effects.

Contribution

It introduces a novel simulation protocol based on ab-initio derived rules and a simple analytical model for Ge condensation during SiGe oxidation.

Findings

Ge atoms segregate near the SiO2/Ge interface during oxidation.

The analytical model accurately reproduces Ge concentration evolution.

Oxidation induces strain that influences Ge condensation.

Abstract

Oxidization of a dilute Si(Ge) alloy is modeled using an original protocol based on molecular dynamics simulation and rules for the oxygen insertions. These rules, deduced from ab-initio calculations, favor the formation of SiO_2 against GeO_2 oxide which leads to segregation of Ge atoms into the alloy during the oxidization front advance. Ge condensation is then observed close to the SiO_2/Ge interface due to the strain induced by oxydization in this region. From the analysis of the simulation process, we propose a one-dimensional description of Ge condensation wich perfectly reproduces the evolution of the Ge concentration during oxidization of the SiGe alloy.