Formation of partially coherent antimony precipitates in ion-implanted thermally annealed silicon

Supersaturated silicon alloys can be produced by ion implantation followed by thermal processing techniques which trap the dopant in substitutional sites but do not allow time for its precipitation. Such systems are metastable, however, and additional thermal processing may cause the precipitation of the dopant in excess of the solubility limit. Here the authors present a detailed characterization of Sb precipitates in Si with respect to structure, shape, orientation, and coherency with the matrix. (100) and (111) Si were implanted with 121Sb+ (200 keV, 4.4 x 1015 cm-2) and recrystallized by solid-phase epitaxial growth at 5500C for 20 min and then heated at 9000C for 40 min. The process of precipitation was found to start with homogeneous nucleation within the SPE-grown layer (which was free of extended defects), which produced precipitates 5-10 nm in diam, centered at the depth corresponding to the mean projected range of the implanted Sb ions. Then dislocation loops formed near the precipitates, which grew and coalesced to produce a planar dislocation network. Precipitates associated with these dislocations coarsened