In this paper we demonstrate the use of dopant segregation during silicidation for decreasing the effective potential barrier height in Schottky-barrier metal-oxide-semiconductor field-effect-transistors (SB-MOSFETs). N-type as well as p-type devices are fabricated with arsenic/boron implanted into the device's source and drain regions prior to silicidation. During full nickel silicidation a highly doped interface layer is created due to dopants segregating at the silicide-silicon interface. This doped layer leads to an increased tunneling probability through the Schottky barrier and hence leads to significantly improved device characteristics. In addition, we show with simulations that employing ultrathin body (UTB) silicon-on-insulator and ultrathin gate oxides allows to further improve the device characteristics.