Nonconservative Ostwald ripening of dislocation loops in silicon

Abstract

We have investigated the effects of the proximity of the surface on the ripening behavior of dislocation loops in preamorphized silicon. Starting from well-defined initial conditions, we have varied the location depth of the loops by successive chemical removal of surface layers and measured changes of the size–distribution function during subsequent annealing by means of transmission electron microscopy. Our results show that the amount of Si atoms bound in the loops is not conserved during annealing and that the loop location depth has a prominent effect on the ripening kinetics. Both these observations prove the nonconservative nature of Ostwald ripening of dislocation loops near wafer surfaces. In addition, we observed different ripening kinetics for annealing in vacuum and in Ar which show that different boundary conditions at the surface are established during annealing in these two ambients.