Practical Work Function Tuning Based on Physical and Chemical Nature of Interfacial Impurity in Ni-FUSI/SiON and HfSiON Systems

The paper demonstrates large effective work function (Phi eff ) modulation towards Si band-edges based on physical and chemical nature of interfacial impurities at Ni-FUSI/SiON and HfSiON interfaces. The authors clarify the influence of Ni-silicide phase on the Phi eff modulation with dopant segregation. Phi eff of 4.14 eV is obtained with a combination of phosphorous ion implantation last (IIL) doping and newly developed low temperature NiSi 2 formation process. The paper also proposed the realistic Phi eff modulation with Al-segregation at Ni-FUSI/HfSiON using IIL-doping process