Skip to main content
Open Access Publications from the University of California

UC Santa Barbara

UC Santa Barbara Previously Published Works bannerUC Santa Barbara

Stability of Ru- and Ta-based metal gate electrodes in contact with dielectrics for Si-CMOS

  • Author(s): Chen, Z Q;
  • Misra, V;
  • Haggerty, R P;
  • Stemmer, Susanne
  • et al.

The Ru-Ta-Si-O, Ta-Si-N-O, and Ru-Ta-Zr-O phase diagrams are important for predicting reactions at interfaces between SiO2 and ZrO2 gate dielectrics and novel Ru and Ta-based metal gate electrodes. Simplified quaternary phase diagrams of the Ru-Ta-Si-O, Ta-Si-N-O, and Ru-Ta-Zr-O systems at 900 degreesC were constructed from known and estimated Gibbs free energy data, respectively. Ru is predicted to be stable in contact with ZrO2 and SiO2, whereas Ta is not stable in contact with SiO2 at temperatures around 900 degreesC. Stoichiometric RuTa and TaN compounds were estimated to be stable in contact with both dielectrics at 900 degreesC. Experimental observations of gate electrode/dielectric interfaces are discussed. They are consistent with the thermodynamic predictions within the limitations of these phase diagrams. Metastable phases, often found in TaN, films, and diffusion of species from the vapor (e.g., oxygen), in particular along grain boundaries in columnar gate electrodes, may lead to reactions not predicted by the equilibrium phase diagrams. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View