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 language | English (US) |
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Pages (from-to) | 197-202 |
Number of pages | 6 |
Journal | Materials Science in Semiconductor Processing |
Volume | 7 |
Issue number | 4-6 SPEC. ISS. |
DOIs | |
State | Published - 2004 |
Keywords
- Defects
- Electron spin resonance
- Hf oxide
- Si/insulator structure