Point defects and dopant diffusion in silicon

TLDR

Diffusion of III‑ and V‑group elements in silicon is reviewed, emphasizing how substitutional dopants interact with vacancies and interstitials during diffusion. The paper aims to unify experimental observations into physical models for simulating dopant diffusion in silicon and to evaluate key parameters and questions about diffusion mechanisms. The authors review experimental data on point‑defect diffusivities and equilibrium concentrations, then illustrate one‑ and two‑dimensional diffusion modeling by solving continuity equations for defects and dopants. Comparisons of simulations with experiments reveal gaps in current models, and the authors summarize recent progress and suggest future research directions.

Abstract

Diffusion in silicon of elements from columns III and V of the Periodic Table is reviewed in theory and experiment. The emphasis is on the interactions of these substitutional dopants with point defects (vacancies and interstitials) as part of their diffusion mechanisms. The goal of this paper is to unify available experimental observations within the framework of a set of physical models that can be utilized in computer simulations to predict diffusion processes in silicon. The authors assess the present state of experimental data for basic parameters such as point-defect diffusivities and equilibrium concentrations and address a number of questions regarding the mechanisms of dopant diffusion. They offer illustrative examples of ways that diffusion may be modeled in one and two dimensions by solving continuity equations for point defects and dopants. Outstanding questions and inadequacies in existing formulations are identified by comparing computer simulations with experimental results. A summary of the progress made in this field in recent years and of directions future research may take is presented.