Wide controllability of flatband voltage by tuning crystalline microstructures in metal gate electrodes

K. Ohmori, T. Chikyow, T. Hosoi, H. Watanabe, K. Nakajima, T. Adachi, A. Ishikawa, Y. Sugita, Y. Nara, Y. Ohji, K. Shiraishi, K. Yamabe, K. Yamada

Research output: Contribution to journalConference articlepeer-review

5 Citations (Scopus)


We propose a novel approach to control the effective workfunction (WF) by taking advantage of crystal structures in metal gate electrodes. The crystal structures determine the predominant material elements at the metal/high-k interface. We have found that, in a Ru-Mo alloy system, a randomly-oriented Ru (fcc) structure promotes the segregation of Mo at the interface, enabling us to achieve a wide controllability of flatband voltage (Vfb) from 0.6-0.8 eV. In addition, the segregation of Mo within a Ru-rich electrode is a key to reducing Fermi level pinning at metal/HfSiON interfaces. Further tunability in Vfb has been examined by employing C-incorporation in the RuMo alloy, thus reducing the crystal grain size and facilitating the control of V fb for a HfSiON (2nm)/SiO2(0.7nm)/Si capacitor. These results demonstrate that the crystal structure control in metal gates is essential for realizing the MIS-FET devices with a short gate length in the 32-22 nm node and beyond.

Original languageEnglish
Article number4418942
Pages (from-to)345-348
Number of pages4
JournalTechnical Digest - International Electron Devices Meeting, IEDM
Publication statusPublished - 2007
Event2007 IEEE International Electron Devices Meeting, IEDM - Washington, DC, United States
Duration: 2007 Dec 102007 Dec 12

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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