Detection of nitrogen incorporation in nm-thin HfO2 layers on (100)Si by electron spin resonance

A. Stesmans, V. V. Afanas'ev, F. Chen, S. A. Campbell

Research output: Contribution to journalArticlepeer-review

Abstract

We report on a low-temperature electron spin resonance (ESR) study of (100)Si/HfO2 entities with ultrathin layers of amorphous (a)- HfO2 deposited by distinct chemical vapor deposition (CVD) techniques using chemically different precursors. The incorporation of N is revealed in (100)Si/HfO2 structures with ultrathin a-HfO2 films deposited by CVD using Hf(NO3)4 as precursor: Upon 60Co γ-irradiation, a prominent ESR powder pattern is observed, which via ESR measurements at two observational frequencies has been incontrovertibly identified as originating from NO2 radicals (density ≥55 at ppm). The molecules are found to be stabilized and likely homogeneously distributed in the a-HfO2 network. Based on symmetry considerations, it is suggested that during deposition, N is incorporated in the HfO2 network as neutral N≡O3 precursors, which are transformed into ESR-active NO2 radicals upon γ-irradiation. The N incorporation appears inherent to the particular nitrado CVD process, an aspect that may bear on the electrical properties of the insulator, such as, e.g., introducing charge traps.

Original languageEnglish (US)
Pages (from-to)197-202
Number of pages6
JournalMaterials Science in Semiconductor Processing
Volume7
Issue number4-6 SPEC. ISS.
DOIs
StatePublished - Dec 10 2004

Keywords

  • Defects
  • Electron spin resonance
  • Hf oxide
  • Si/insulator structure

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