Morphological and electrical characterization of AI/Ni/n-lnP contacts with tapered insertion Ni-Layer

The addition of a thin Ni layer has improved the surface morphology of Al/n-InP contacts which show an enhanced Schottky barrier height (SBH) after rapid thermal annealing. In order to determine the optimum thickness of the insertion Ni layer, we have fabricated a unique sample in which the thickness of the insertion Ni layer tapered off in space. The improvement of the surface morphol-ogy as well as the SBH enhancement were realized by inserting 35 nm Ni layer annealed at rather low temperatures (around 450°C). The solid-phase reaction between Ni and InP might play an important role in the low-temperature formation of A1P which was responsible for the SBH enhancement.