Cold Silicon Preamorphization Implant and Presilicide Sulfur Implant for Advanced Nickel Silicide Contacts

We report the first demonstration of a nickel silicide (NiSi) contact formation technique using cold silicon (Si) preamorphization implant (PAI) combined with presilicide sulfur (S) implant. The cold Si PAI suppresses the agglomeration of NiSi film at elevated temperatures. Presilicide S implant and its segregation at the interface of NiSi and n-type Si (n-Si) after silicidation significantly lowers the effective Schottky barrier height (Φⁿ_B) for electrons at the NiSi/n-Si contact. The S atoms in Si could be modeled as donor-like traps near the NiSi/n-Si interface, and a simulation study was performed to explain the reduction of Φⁿ_B caused by S.