Dynamic segregation of metallic impurities at SiO2/Si interfaces

18th Microscopy of Semiconducting Materials Conference

物理学;材料科学

De Luca, A.^1 ; Portavoce, A.^1 ; Texier, M.^1 ; Burle, N.^1 ; Pichaud, B.^1

IM2NP, UMR7334 CNRS - Aix-Marseille Université, Campus de Saint-Jérôme, Av. Escadrille Normandie Niémen, F-13397 Marseille Cedex, France^1

关键词: Atom probe tomography;    Cluster formations;    Concentration profiles;    Metallic contamination;    Metallic impurity;    Oxidation front;    Oxidation of Fe;    Pyramidal defects;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/471/1/012029/pdf
DOI  :  10.1088/1742-6596/471/1/012029

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The behaviour of two metallic impurities, iron and tungsten, during oxidation of silicon wafers has been investigated using transmission electron microscopy and atom probe tomography. Metallic contamination has been introduced by implantation of54Fe at 65 keV and186W at 150 keV, with a dose of 1015at/cm2. Oxidation of Fe-contaminated Si wafer results in the precipitation of iron as β-FeSi2at the SiO2/Si interface. The presence of these precipitates hinders the oxidation front which forms silicon pyramidal defects. Further oxidation of the precipitates leads to iron-rich cluster formation in the SiO2layer, surrounding the pyramids. Dry oxidation of a tungsten-contaminated Si wafer is characterised by the formation of nanometric spherical precipitates in the Si layer. The size and density of these precipitates versus depth follow the as-implanted W concentration profile.