Enhancement of silicon oxidation rate due to tensile mechanical stress

Oxidation of silicon wafers under external mechanical stress was studied in this work. From the oxide thickness profile measured by an automatic ellip someter, it was found that the oxidation kinetics of silicon was affected b y the mechanical stress. The tensile stress strongly enhances the oxidation rate of silicon. A concept was proposed to explain this phenomenon by usin g a well-known physical Si-SiO2 lattice model. The tensile stress in the si licon will enlarge the atom spacing of silicon and make the oxidation to be easier and faster. A simulated deformation of silicon substrate under tens ile stress was also given to support this concept. This work is a direct ev idence of the effect of mechanical stress on silicon oxidation. (C) 2000 Am erican Institute of Physics. [S0003-6951(00)02714-5].