Implementation of nitride oxidation in the 2D process simulator IMPACT-4

To shrink the dimension of devices, new isolation technologies, with respect to classical LOCOS, have to be evaluated. This paper deals with the study of one of these possible alternatives: the LOCOS/Recessed-LOCOS NCLAD structure. In this process a thin nitride layer encapsulates the oxide-nitride stack to prevent the formation of long bird's beak. The efficiency of this technique is dependent on the nitride oxidation. In order to study this process, via simulation, it is therefore necessary to model nitride oxidation: a "modified Deal and Grove" model has been implemented and calibrated in the 2D Process simulator IMPACT-4. The implementation problems and relative solutions are described.