Schottky barrier height modulation using dopant segregation in Schottky-barrier SOI-MOSFETs

The effect of dopant segregation (DS) on the electrical behavior of silicon-on-insulator Schottky barrier MOSFETs (SB-MOSFETs) is investigated. Ion implantation with arsenic and boron and subsequent silicidation is used to create highly n- and p-doped interface layers at the silicide-silicon interface. As a result, a strong band bending occurs at the silicide-silicon interface giving rise to a lowering of the effective Schottky barrier height. In turn, an increased electron as well as hole injection into the channel leads to improvements of the off- and on-state of the SB-MOSFETs. Using dopant segregation n-type as well as p-type SB-MOSFETs with nickel silicide source/drain electrodes have been fabricated exhibiting an inverse sub-threshold slope close to the thermal limit and showing one order of magnitude higher on-currents if compared to SB-MOSFETs without DS. In essence, the use of dopant segregation allows the fabrication of high performance Schottky barrier MOSFETs.