Patricia Almeida Carvalho, Annett Thørgesen, Quanbao Ma, Daniel Nielsen Wright, Spyros Diplas, Augustinas Galeckas, Alexander Azarov, Valdas Jokubavicius, Jianwu Sun, Mikael Syväjärvi, Bengt Gunnar Svensson, Ole Martin Løvvik
SciPost Phys. 5, 021 (2018) ·
published 6 September 2018
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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.
