Transmission electron microscopy study of SiF+/BF2+ implanted and annealed (100)Si: Amorphization and residual effects

Abstract

Formation of amorphous layers and residual defects in SiF+/BF2+ implanted and annealed (100)Si was investigated on an atomic level by using a high-resolution transmission electron microscope. Amorphous layers, of which depths were about 70% of those of amorphous layers formed by Si+ preamorphization at the same implantation energies, could be formed by SiF+ preamorphization. Two distinct layers of defects were formed in SiF+/BF2+ implanted wafers annealed at 600 degrees C for 1 h and then rapidly thermally annealed at 950 degrees C for 30 s. One layer, observed near the surface regions, consisted of intrinsic stacking faults bounded by 30 degrees Shockley partial dislocations, twins, amorphous regions, and fine clusters. The other layer, observed near the original amorphous/crystalline interface, consisted of Frank partial dislocations of which Burgers vector is 1/3a[111] and 60 degrees perfect dislocations of which Burgers vector is 1/2a[110]. These defects were formed by retarding growth rate by fluorine atoms; outdiffusion of fluorine atoms; lattice misorientation between the substrate and crystalline pockets; and the introduction of an extra halfplane during the preamorphization process. (C) 1996 American Institute of Physics.