Numerical Simulation of Plasma Immersion Ion Implantation and Diffusion

A numerical model is proposed to simulate plasma immersion ion implantation (PIII) and diffusion. The PIII process is modeled by the 1-D hybrid particle-in-cell ions and Boltzmann distribution of electrons. The depth profile of the as-implanted atoms is modeled by transport-of-ions-in-matter-based method. Diffusion of the implanted atoms is modeled by Fick´s diffusion equation, assuming that the diffusion coefficient is independent of location and time. It is shown that PIII at a high temperature will generate a more shallow depth profile than the process of PIII at low temperature, followed by high-temperature annealing. In the extreme case of fast diffusion, the PIII at high temperature reveals a standard erfc (error function) distribution profile of constant-surface-concentration diffusion, and the process of PIII at low temperature, followed by high-temperature annealing, reveals a Gaussian distribution profile of constant-total-dopant diffusion.