Numerical modeling of nonplanar oxidation coupled with stress effects

The study focuses on the numerical solution method based on a finite-difference approach with the coordinate transformation method for simulating the nonplanar oxide growth. A relaxation technique is introduced to incorporate the stress effect into oxidation kinetic equations maintaining numerical stability. In addition, for simulating the stress-dependent oxide growth, the role of the boundary condition at the free-oxide surface is discussed. The present method allows an accurate evaluation of the local stress distribution in nonplanar oxide structures and realizes the precise simulation of oxide shapes under the large stress effect. They are demonstrated in applications to both the LOCOS process with thick nitride film and the trench oxidation process, which strongly depends on the oxidation-induced stress at trench corners