Kinetics and Mechanism of Nanostructures in Oxidation of Si1—xGex Alloys

We investigate the oxidation behaviour of Si1-xGex alloys(x=0.05,0.15,and 0.25),The oxidation of SiGe films with different compositions was carried out in O2(dry)atmosphere at 800,900 and 1000℃,respectively,for various lengths of time,The thickness and property of the nanoparticle and nanolayer in oxide films and germanium segregation in oxidation of SiGe alloys are measured by using a high precision ellipsometer.The results are in good agreement with the Rutherford backscattering spectrometry,profile dektak instrument and high-resolution scanning transmission electron microscopy.We found that the Ge content in the oxide layer increases with the Ge content in SiGe alloys,and that the Ge content in the oxide film decreases with the increasing oxidation temperature and time,Rejection of Ge results in Piling up of Ge at the interface etween the growing SiO2 and the remaining SiGe,which forms a nanometre Ge-rich layer.Substantial interdiffusion of Si and Ge takes place in the remaining SiGe,which leads to the complicated distribution of Ge segregation.We find a nanometre cap layer over the oxide film after fast oxidation,in which there are many Ge nanoparticles,We analyse the kinetics and mechanism of the nanostructure of the oxide and Ge segregation in oxidation of Si1-xGex alloys.