Dopant Diffusion

This chapter discusses the primarily with the atomistic theory of diffusion in silicon. To motivate our discussions and to highlight the relevant issues for dopant diffusion, as it pertains to complementary metal oxide semiconductor, we quote the following from the International Technology Roadmap for Semiconductors. The result will then be generalized for the case of several kinds of defects with internal degrees of freedom, and finally, the equilibrium between the different charge states of a defect will be considered. At thermal equilibrium, the fraction of the lattice sites vacant in intrinsic Si is given by the equation where is the free energy for formation of a vacancy. The chapter also discusses the formulation for dopant diffusion under non-equilibrium conditions. However, there are many open questions about the effect of strain on dopant diffusion, such as the impact on the diffusion pathway and migration barrier.