  Boron (B) has the potential for generating an intermediate band in cubic
silicon carbide (3C-SiC), turning this material into a highly efficient
absorber for single-junction solar cells. The formation of a delocalized band
demands high concentration of the foreign element, but the precipitation
behavior of B in the 3C polymorph of SiC is not well known. Here,
probe-corrected scanning transmission electron microscopy and secondary-ion
mass spectrometry are used to investigate precipitation mechanisms in
B-implanted 3C-SiC as a function of temperature. Point-defect clustering was
detected after annealing at 1273 K, while stacking faults, B-rich precipitates
and dislocation networks developed in the 1573 - 1773 K range. The precipitates
adopted the rhombohedral B13C2 structure and trapped B up to 1773 K. Above this
temperature, higher solubility reduced precipitation and free B diffused out of
the implantation layer. Dopant concentrations E19 at.cm-3 were achieved at 1873
K.
