The influence of charge states and elastic stresses on the diffusion of point defects in silicon

The properties of nanostructures such as ultrathin layers 50 nanometers in thickness or smaller are strongly dependent on the state of a defect subsystem in the layers. The objective of this paper is to study the influence of charge states and internal elastic stress on the transport of point defects in silicon. The equation for the diffusion of point defects taking into account the contributions of different charge states of defects to the transport process is reduced to the form convenient for numerical solution. For this purpose, the effective diffusivity of point defects was obtained as a function of the dopant concentration and empirical parameters. The effective coefficient of the absorption of point defects by immobile sinks was also obtained in a similar convenient form. Using the modified equation for the diffusion of point defects, we have simulated the transport processes of diffusing species for different charge states of defects and nonuniform dopant distributions. The cases of zero and nonzero elastic stress were investigated.