Modeling of Si self-diffusion in SiO2: Effect of the Si/SiO2 interface including time-dependent diffusivity

Abstract

Self-diffusion of Si in thermally grown SiO2 is modeled taking into account the effect of SiO molecules generated at the Si/SiO2 interface and diffusing into SiO2 to enhance the self-diffusion. Based on the model, a recent self-diffusion experiment of ion-implanted Si30 in SiO2, which showed increasing self-diffusivity with decreasing distance between the Si30 diffusers and Si/SiO2 interface [Fukatsu et al., Appl. Phys. Lett. 83, 3897 (2003)], was simulated, and the simulated results fit the experimental profiles. Furthermore, the simulation predicts that the self-diffusivity would increase for a longer annealing time because more SiO molecules should be arriving from the interface. Such time-dependent diffusivity was indeed found in our follow-up experiments, and the profiles were also fitted by the simulation using a single set of parameters.