Impact of work function optimized S/D silicide contact for high current drivability CMOS

A formation process of the silicide/Si contact with low contact resistance in the source/drain (S/D) regions has been developed in order to reduce the S/D electrode series resistance of MOSFETs. Er that has a low Schottky barrier height (SBH) for electrons and Pd that has a low SBH for holes were selected to n⁺- and p⁺-Si, respectively. The silicide formation processes were carried out in N₂ ambient from the Si-surface cleaning before the metal depositions to the silicidation anneal in order not to expose metal and Si region so as to prevent the oxidation. A W capping layer was formed on the Er-surface to prevent it from oxidation, since it is very easily oxidized because of its low work function. These silicides were applied to Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), which improved the current drivability of n- and p-MOSFET due to the reduction of the S/D electrodes series resistance.