2D PROCESS SIMULATION OF DOPANT DIFFUSION IN POLYSILICON

A new model to describe dopant diffusion and recrystallisation in polycrystalline silicon during thermal treatment is presented. The full 3D microstructure of the material is considered and a local homogenisation approximation introduced. A parallel diffusion model for diffusion in grain boundaries and grain interior with grain growth and segregation is developed within this approximation. The model is solved in a 2D vertical section using a finite element discretisation. An example of the application of this model to a one micron bipolar transistor is given.