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

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-As pairs at 450 K leads to the formation of V-As₂ complexes, which in turn convert to stable V-As₃ defects at 700 K. These processes manifest the formation of V-As₃ 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.