Polarity dependent Al-Ti contacts to 6H-SiC

In this paper, an Al-Ti contact preparation method is described on 6H-SiC wafers. The Al and Ti were both separately deposited and co-deposited onto Si→C polarized (0 0 0 1-bar) C and C→Si polarized (0 0 0 1) Si faces of SiC substrate by dc magnetron sputtering. The samples were annealed at 1000 deg. C in N2 atmosphere. The phase and morphology of the formed contacts were investigated by transmission electron microscopy. The formed contacts clearly showed polarity dependence on SiC substrate. When the SiC substrate was Si→C polarized the binary Al3Ti phase generated. When it was C→Si polarized the ternary Ti3SiC2 formed along with the Al3Ti resulting in a bilayered contact structure