Phase effects and short gate length device implementation of Ni fully silicided (FUSI) gates

J. A. Kittl, M. A. Pawlak, A. Lauwers, C. Demeurisse, T. Hoffmann, A. Veloso, K. G. Anil, S. Kubicek, M. Niwa, M. J.H. van Dal, O. Richard, M. Jurczak, C. Vrancken, T. Chiarella, S. Brus, K. Maex, S. Biesemans

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


A study of the implementation of Ni fully silicided (FUSI) gates to scaled devices is presented, addressing the issue of phase control at short gate lengths. A linewidth effect for Ni FUSI gates is found for non-optimized processes targeting NiSi, with formation of NiSi at long gate lengths and Ni-rich silicides at short gate lengths. This is attributed to Ni diffusion from areas surrounding the gates, resulting in a larger reacted Ni-Si ratio at short gate lengths. The linewidth dependence of the Ni FUSI phase results in an undesirable kink in the Vt roll-off characteristics, due to the difference in effective work function between the Ni silicide phases, which is particularly large for HfSiON dielectrics. An optimized 2-step RTP silicidation process is shown to eliminate this problem allowing the formation of NiSi gates uniformly at all gate lengths. The application and scalability of Ni-rich silicides to PMOS devices is also demonstrated, as well as a scheme for CMOS integration of dual WF phase controlled FUSI (NiSi for NMOS and Ni-rich silicides for PMOS), using an etch back step to reduce the poly-Si height on PMOS electrodes before full silicidation.

Original languageEnglish
Pages (from-to)2117-2121
Number of pages5
JournalMicroelectronic Engineering
Issue number11-12
Publication statusPublished - 2006 Nov 1
Externally publishedYes


  • CMOS
  • FUSI gates
  • Ni-rich silicides
  • NiSi

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering


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