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.>

A description is given of a three-dimensional process simulator, named SMART-P, that is based on the finite-difference approach to the supercomputer FACOM VP-100. To simulate the impurity redistribution and nonplanar structure in the Si/SiO/sub 2/ system, this simulator contains a three-dimensional oxidation model, an interaction model of impurities, a numerical model of interstitial-assisted oxidation-enhanced diffusion, and other process models. The numerical process modeling in the Si/SiO/sub 2/ system is described. The three-dimensional process modeling CAD (computer-aided design) has been realized by using efficient numerical algorithms based on the generalized coordinate transformation method. The capabilities of this simulator have been demonstrated in applications relating to both local oxidation of silicon (LOCOS) and trench-isolated 0.5 mu m MOSFET structures.>