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

Abstract
We have investigated diffusion and activation of boron implanted with 6 keV energy to a maximum concentration of 8.0 × 10 20 atoms ∕ cm 3 in crystalline germanium ( c -germanium) and preamorphized germanium, employing rapid thermal annealing in the range of 400–600 °C. As-implanted boron profiles in preamorphized germanium are shallower than the ones in c -germanium due to channeling suppression. While borondiffusion 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 2.4 × 10 20 atoms ∕ cm 3 has been found in regrown germanium, while a level of only 1.2 × 10 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.
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