Diffusion, activation, and recrystallization of boron implanted in preamorphized and crystalline germanium

We have investigated diffusion and activation of boron implanted with 6 keV energy to a maximum concentration of 8.0x10(20) atoms/cm(3) in crystalline germanium (c-germanium) and preamorphized germanium, employing rapid thermal annealing in the range of 400-600 degrees C. As-implanted boron profiles in preamorphized germanium are shallower than the ones in c-germanium due to channeling suppression. While boron diffusion is not observed either in c-germanium or during the germanium regrowth from amorphous state, the boron activation level achieved from the two starting phases is significantly different. A boron activation level of 2.4x10(20) atoms/cm(3) has been found in regrown germanium, while a level of only 1.2x10(19) atoms/cm(3) is observed in c-germanium. Remarkably, there is no evidence of any residual extended defectivity at the original crystalline/amorphous interface, when preamorphization is performed. (C) 2005 American Institute of Physics.