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

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.