Positron annihilation experiments were applied to verify the formation mechanism of electrically inactive vacancy-impurity clusters in highly n-type Si. It was shown that the migration of V-As pairs at 450K led to the formation of V-As2 complexes which, in turn, changed to stable V-As3 defects at 700K. 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 post-growth heat treatment at 700K.

Formation of Vacancy-Impurity Complexes by Kinetic Processes in Highly As-Doped Si. V.Ranki, J.Nissilä, K.Saarinen: Physical Review Letters, 2002, 88[10], 105506 (4pp)