MORPHOLOGICAL AND ELECTRICAL CHARACTERIZATION OF AL NI/N-INP CONTACTSWITH 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 thi ckness of the insertion Ni layer, we have fabricated a unique sample i n which the thickness of the insertion Ni layer tapered off in space. The improvement of the surface morphology as well as the SBH enhanceme nt were realized by inserting 35 nm Ni layer annealed at rather low te mperatures (around 450 degrees C). The solid-phase reaction between Ni and InP might play an important role in the low-temperature formation of AIP which was responsible for the SBH enhancement.