  The electrical behavior of Ni Schottky barrier formed onto heavily doped
(ND>1019 cm-3) n-type phosphorous implanted silicon carbide (4H-SiC) was
investigated, with a focus on the current transport mechanisms in both forward
and reverse bias. The forward current-voltage characterization of Schottky
diodes showed that the predominant current transport is a thermionic-field
emission mechanism. On the other hand, the reverse bias characteristics could
not be described by a unique mechanism. In fact, under moderate reverse bias,
implantation-induced damage is responsible for the temperature increase of the
leakage current, while a pure field emission mechanism is approached with bias
increasing. The potential application of metal/4H-SiC contacts on heavily doped
layers in real devices are discussed.
