Impact of channel doping on Schottky barrier height and investigation on p-SB MOSFETs performance

This paper proposes to study the impact of a moderate variation of the channel doping level on the electrical performance of p-type Schottky-barrier (SB) MOSFETs. First, it has been found that a moderate increase of the acceptors doping level leads to a reduction of the Schottky-barrier height (SBH) but does not affect the silicide reaction. In the case of PtSi, the SBH on p-type silicon at 5 × 1015 cm−3 is 0.15 eV whereas an increase of the doping level by two decades decreases the barrier by 60 meV. The integration of PtSi MOSFETs on moderately doped channel (5 × 1017 cm−3) was successfully achieved, demonstrating an overall 60% improvement in current drive at Lg = 100 nm. This enhanced performance is attributed to the barrier height reduction related to the beneficial band bending induced by p-type dopants. The considered doping levels are still in a sufficiently low range not to affect the carrier mobility in the channel. A complete study, including comparison of Ion, Ioff, immunity against short channel effects (Swing and DIBL), is presented.