Two-dimensional oxidation

This paper introduces the first general two-dimensional oxidation model based on steady-state oxygen diffusion and the slow incompressible viscous flow of oxide. The moving-boundary problem is solved through a novel numerical technique based on pressure/velocity iteration and a boundary-value approach. The simulation results obtained for oxide shape and bird´s beak size versus pad-oxide thickness are in excellent agreement with experiments. This model is also able to calculate stress on the silicon interface during oxidation; this calculated value (6 × 10⁹dyne/cm²) also agrees with the measurement and reveals the tendency of stress to decrease with increasing pad-oxide thickness.