Two-dimensional thermal oxidation of silicon. II. Modeling stress effects in wet oxides

For pt.I see ibid., vol.ED-34, p.1008-17 (May 1987). The authors propose that the stress from two-dimensional oxide deformation affects the kinetic parameter in the Deal-Grove model (1965). In particular, the viscous stress associated with the nonuniform deformation of the oxide is identified as the fundamental force of retardation. In this model, the stress normal to the Si-SiO₂ interface reduces the surface reaction rate in both convex and concave surfaces, whereas the stress in the bulk of the oxide (compressive for concave and tensile for convex surfaces) is responsible for the thinner oxides on the concave structures. The model is described by a simplified mathematical formulation made possible by the symmetry in cylindrical structures. Comparisons with experimental data, possible applications, and limitations of the model are also discussed