Analysis of Fermi level pinning characteristics in erbium silicided metal–semiconductor interface

Abstract

In this work, the Fermi level pinning phenomena in erbium-silicided metal–semiconductor Schottky contact is investigated for the understanding on the difficulties forming ohmic contacts between metal and semiconductor materials. The work function of erbium-silicide is extracted by using UPS (ultraviolet photoelectron spectroscopy) and I–V (current–voltage) method with metal–semiconductor diode pattern, respectively. In UPS analysis, the extracted workfunction gradually decreased with increase in the deposited erbium-silicide and saturated to 3.8 eV with 500 Å thick erbium-silicide. However, the extracted work function value of erbium-silicide by I–V method from erbium-silicide on p-type silicon substrate diode pattern is 4.4 eV which shows the strong Fermi level pinning phenomena in erbium-silicided Schottky contact. From the numerical model analysis, the main reason for Fermi level pinning in erbium-silicide is mainly attributed due to the metal induced gap state rather than chemical bonding at interface. Finally, this analysis method will be very effective for the analysis in Fermi level pinning phenomena in metal–semiconductor Schottky contacts.