Preliminary study on the effect of micrometric Ge-droplets on the characteristics of Ni/4H-SiC Schottky contacts

This work reports on the morphological and electrical characteristics of Ni/4H-SiC Schottky contacts, fabricated on epitaxial layers intentionally covered by micrometric size Gedroplets. Specifically, the Ge-droplets behave as preferential paths for the vertical current conduction, as observed at nanometric scale by conductive atomic force microscopy. As a consequence, the electrical I-V characteristics of these Ni contacts revealed the presence of a double-barrier, thus indicating an inhomogeneity in the interface. This behavior was associated to the local Schottky barrier lowering contribution due to the Ge-presence. These results can be useful to explore the possibility of controlling the contact (Schottky or Ohmic) properties by changing the size and the distribution of the surface impurities.