Metal-gate-induced reduction of the interfacial layer in Hf oxide gate stacks

L. V. Goncharova, M. Dalponte, T. Gustafsson, O. Celik, Eric Garfunkel, P. S. Lysaght, G. Bersuker

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The properties of high- κ metal oxide gate stacks are often determined in the final processing steps following dielectric deposition. We report here results from medium energy ion scattering and x-ray photoelectron spectroscopy studies of oxygen and silicon diffusion and interfacial layer reactions in multilayer gate stacks. Our results show that Ti metallization of Hf O2 Si O2 Si stacks reduces the Si O2 interlayer and (to a more limited extent) the Hf O2 layer. We find that Si atoms initially present in the interfacial Si O2 layer incorporate into the bottom of the high- κ layer. Some evidence for Ti-Si interdiffusion through the high- κ film in the presence of a Ti gate in the crystalline Hf O2 films is also reported. This diffusion is likely to be related to defects in crystalline Hf O2 films, such as grain boundaries. High-resolution transmission electron microscopy and corresponding electron energy loss spectroscopy scans show aggressive Ti-Si intermixing and oxygen diffusion to the outermost Ti layer, given high enough annealing temperature. Thermodynamic calculations show that the driving forces exist for some of the observed diffusion processes.

Original languageEnglish
Pages (from-to)261-268
Number of pages8
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume25
Issue number2
DOIs
Publication statusPublished - 2007

Fingerprint

Oxides
Metals
oxides
metals
Oxygen
Crystalline materials
Electron energy loss spectroscopy
Silicon
Photoelectron spectroscopy
High resolution transmission electron microscopy
Metallizing
ion scattering
oxygen
Multilayers
Grain boundaries
x ray spectroscopy
Thermodynamics
metal oxides
Scattering
Annealing

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Surfaces and Interfaces
  • Physics and Astronomy (miscellaneous)

Cite this

Metal-gate-induced reduction of the interfacial layer in Hf oxide gate stacks. / Goncharova, L. V.; Dalponte, M.; Gustafsson, T.; Celik, O.; Garfunkel, Eric; Lysaght, P. S.; Bersuker, G.

In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, Vol. 25, No. 2, 2007, p. 261-268.

Research output: Contribution to journalArticle

Goncharova, L. V. ; Dalponte, M. ; Gustafsson, T. ; Celik, O. ; Garfunkel, Eric ; Lysaght, P. S. ; Bersuker, G. / Metal-gate-induced reduction of the interfacial layer in Hf oxide gate stacks. In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films. 2007 ; Vol. 25, No. 2. pp. 261-268.
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