Barrier height control of Pd 2 Si/Si schottky diodes using diffusion from doped Pd

The barrier height of metal-semiconductor contacts can be varied within wide limits by a suitable doping (Sb, Al) of the metal layer itself and application of a temperature treatment to the sandwich structure. As a result the doping elements are weakly diffused into the semiconductor surface. This leads to a change of the band bending and finally to a change of the barrier height. {Pd₂Si}/{n- Si} diodes with barrier heights q· φ_B between 0.5 and 0.8 eV were fabricated reproducibly by this method. The barrier height of undoped Pd ₂Si/Si contacts equals 0.72 eV. The doping elements were introduced into the metal layer by partly covering the Pd-cathode of a DC-sputtering apparatus with Al or Sb, and subsequent sputtering of the composite cathode onto the silicon slices. The concentration of doping elements in the sputtered metal layer is given by the relation of the part of the cathode surface covered with the doping element to the whole cathode surface.