Computational methods for the simulation of the excimer laser annealing in MOS technology

摘要

The integration of the laser annealing process in metal-oxide-semiconductor (MOS) technology requires predictive codes for the simulation of the material modification due to the interaction between the laser radiation and the structure. These computational tools have a two-fold aim, i.e. (a) the estimate of the heat sources space distribution in the specimen, and (b) the simulation of the phenomena occurring inside the specimen during the irradiation (thermal field evolution, melting and re-growth of localised zones, dopant re-distribution). Our modelling is based on a coupled finite-difference-time-domain and phase-field method, which is applied in the simulation of the irradiation and the structural evolution, respectively. We considered a simulation framework of a typical transistor structure, i.e. the implanted impurity profiles in two-dimensional (2D) samples containing a SiO_2/a-Si/c-Si stack. The model is calibrated for the cases of different impurity atoms. Our results demonstrate the necessity of a complete numerical approach. In particular, the effects of the device geometry and the optical/thermal properties of the material used are discussed in detail.