Formation of Vacancy-Impurity Complexes by Kinetic Processes in Highly As-Doped Si

Abstract

Positron annihilation experiments have been applied to verify the formation mechanism of electrically inactive vacancy-impurity clusters in highly $n$-type Si. We show that the migration of $V\ensuremath{-}\mathrm{As}$ pairs at 450 K leads to the formation of $V\ensuremath{-}{\mathrm{As}}_{2}$ complexes, which in turn convert to stable $V\ensuremath{-}{\mathrm{As}}_{3}$ defects at 700 K. These processes manifest the formation of $V\ensuremath{-}{\mathrm{As}}_{3}$ as the dominant vacancy-impurity cluster in highly $n$-type Si. They further explain the electrical deactivation and clustering of As in epitaxial or ion-implanted Si during postgrowth heat treatment at 700 K.