Widely tunable work function TaN/Ru stacking layer on HfLaO gate dielectric

X. P. Wang*, M. F. Li, H. Y. Yu, J. J. Yang, J. D. Chen, C. X. Zhu, A. Y. Du, W. Y. Loh, S. Biesemans, Albert Chin, G. Q. Lo, D. L. Kwong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


For the first time, we demonstrate experimentally that using HfLaO high-κ gate dielectric and vertical stacks of TaN/Ru metal layers, dual metal gates with continuously tunable work function over a very wide range from 3.9 to 5.2 eV, can be achieved after 1000 °C annealing required by a conventional CMOS source/drain activation process. The wide tunability of work function for this bilayermetal structure is attributed to metal interdiffusion during annealing and the release of Fermi level pinning between metal gates (Ru and TaN) and HfLaO. Moreover, this change is thermally stable and unaffected by a subsequent high temperature process.

Original languageEnglish
Pages (from-to)50-53
Number of pages4
JournalIEEE Electron Device Letters
Issue number1
StatePublished - 1 Jan 2008


  • CMOS
  • Fermi level pinning
  • HfLaO
  • High-κ dielectric
  • Interdiffusion
  • Metal gate
  • Work function

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