One important topic in numerical semiconductor process simulation is the thermal oxidation of silicon. The process step can be described as a transient coupled system of equations for oxidant diffusion, chemical reaction and large mechanical displacement. A moving interface between oxide and silicon renders the whole system a free boundary problem. Moreover, a volume expansion during oxidation by a factor of more than two causes the overall domain of computation to change during simulation. The approach which is presented in this paper, uses the idea of a distributed reaction zone between silicon and oxide. A finite element discretization for this formulation shows significant advantages over conventional approaches. In numerical examples an excellent agreement of the simulated results with microscopical photographs of real structures is demonstrated.     «

One important topic in numerical semiconductor process simulation is the thermal oxidation of silicon. The process step can be described as a transient coupled system of equations for oxidant diffusion, chemical reaction and large mechanical displacement. A moving interface between oxide and silicon renders the whole system a free boundary problem. Moreover, a volume expansion during oxidation by a factor of more than two causes the overall domain of computation to change during simulation. The...     »