Effective Modulation of Ni Silicide Schottky Barrier Height Using Chlorine Ion Implantation and Segregation

Using a presilicide implantation approach, we demonstrate that the Schottky barrier height (SBH) of NiSi/n-Si(100) can be modulated by doping a Si substrate with a halogen species such as chlorine. Activation energy measurements indicate that an ultralow barrier of 0.08 eV for NiS/n-Si can be achieved when a high dose (~1 times 1015cm2) of chlorine is implanted prior to Ni silicidation. A secondary ion mass spectroscopy analysis on the presilicide Cl-implanted NiSi shows chlorine segregates at the interface with SBH tuning from 0.68 to 0.08 eV on n-Si and a corresponding increase in hole SBH on p-Si(100). The presilicide Cl-implanted NiSi film also demonstrates an enhanced thermal stability with a low sheet resistively of < 28 muOmega even up to 850degC.