Barrier-height fixation in dc-sputtered Au-p silicon Schottky barriers

Abstract

The sputter deposition of Au on p-silicon has been studied by means of forward and reverse current voltage characteristics. Barrier heights have been determined from Fowler plots and from activation energies. The observed increase of the barrier height with respect to evaporated contacts is mainly dependent on features of the discharge like the sputtering voltage, deposition time, gas composition, and pressure. It is for the most part independent of the semiconductor pretreatment before deposition or on the thickness of an insulating thin (<10 nm) layer. For low sputter voltages (<1 kV) there is an increase of the barrier height with increasing sputter voltage. Sputter voltages exceeding 1 kV result in a fixation of the barrier height at 0.60–0.65 eV. This fixation is due to the presence of sputter-induced traps in a thin surface layer of about 10 nm.