Evolution of boron-interstitial clusters in crystalline Si studied by transmission electron microscopy

The thermal evolution of large boron-interstitials clusters (BICs) in crystalline Si has been studied by transmission electron microscopy (TEM). After ion implantation (20 keV and 1x10(14) Si/cm(2)) and annealing (815 degrees C and 5 min), large clusters (6-8 nm) have been observed in correspondence of a narrow, highly doped Si:B layer (2x10(20) B/cm(3)). Under prolonged annealing, such clusters dissolve, progressively shrinking their mean size below the TEM detection limit. The time evolution of such a BIC shrinking is fully compatible with the slow path dissolution kinetics recently published. These data suggest the identification of the slow dissolving BICs with the large observed clusters. (C) 2007 American Institute of Physics.