Oxidation-induced stress in a LOCOS structure

A two-dimensional oxidation model is introduced to analyze stresses induced in the oxide during silicon thermal oxidation for a local oxidation of silicon (LOCOS) structure. In this model, it is assumed that oxidation consists of two basic processes: oxidant diffusion into the oxide and viscoelastic deformation of the oxide. The equations describing these processes are solved using the boundary element method. Information on the stress distribution in the oxide suggests that the LOCOS oxide shape is closely related to the oxidation-induced stress. Consequently, this should prove useful in understanding thermal oxidation.