Uv activated surface preparation of silicon for high-k dielectric deposition

Casey C. Finstad, Anthony J. Muscat

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


High-k gate materials, such as HfO2, are unstable on silicon and form low permittivity interfacial oxides when heated. A single layer of silicon nitride grown prior to gate dielectric deposition could serve as a diffusion barrier to prevent oxide formation. A monolayer film of surface amine groups will be chemically similar to surface hydroxyl groups, and could also serve as a seed layer to promote the nucleation of a high-k film. The deposition of amines (≡Si-NH2 or ≡Si-NH-Si≡) on chlorine and hydrogen terminated Si(100) at low temperature (<100°C) was investigated using x-ray photoelectron spectroscopy (XPS). UV-Cl2 exposures (0.1-10 Torr Cl2 at 25-150°C, 10-600 s, 1000 W Xe lamp) were used to terminate Si(100) with Cl atoms. Exposure to NH3 (0.1-1000 Torr, 75°C, 5-60 min) replaced Cl atoms with up to 0.3 ML of amine groups, as measured by XPS. Cl atoms served as reactive leaving groups, lowering the overall activation energy barrier for nitridation. Alternatively, UV photons with energy greater than 5.7 eV were used to photodissociate NH3 molecules, yielding NH2 photofragments that reacted with the H-terminated Si(100) surface. At aUV photon flux of 19 mW/cm2, the N coverage increased with time and saturated at ~1 ML. Significant oxygen was observed on the surface due to H2O contamination in the source gas.

Original languageEnglish (US)
Title of host publicationUltra Clean Processing of Silicon Surfaces VII
EditorsPaul Mertens, Marc Meuris, Marc Heyns
PublisherTrans Tech Publications Ltd
Number of pages4
ISBN (Print)9783908451068
StatePublished - 2005
Externally publishedYes
Event7th International Symposium on Ultra Clean Processing of Silicon Surfaces, UCPSS 2004 - Brussels, Belgium
Duration: Sep 20 2004Sep 22 2004

Publication series

NameSolid State Phenomena
ISSN (Print)1012-0394
ISSN (Electronic)1662-9779


Other7th International Symposium on Ultra Clean Processing of Silicon Surfaces, UCPSS 2004


  • Ammonia
  • Atomic layer deposition (ALD)
  • Chlorine
  • Diffusion barrier
  • Seed layer
  • Silicon nitride
  • Ultraviolet
  • XPS

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics


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