Composition control and ferroelectric properties of sidewalls in integrated three-dimensional SrBi2Ta2O9-based ferroelectric capacitors
The difficult scaling of ferroelectric random access memories with the complementary metal-oxide semiconductor technology roadmap requires integration of three-dimensional (3D) ferroelectric capacitors (FeCAP’s). In this work the unusual electrical behavior of 3D FeCAP sidewalls was studied by compa...
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Veröffentlicht in: | Journal of applied physics 2005-09, Vol.98 (5) |
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Hauptverfasser: | , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The difficult scaling of ferroelectric random access memories with the complementary metal-oxide semiconductor technology roadmap requires integration of three-dimensional (3D) ferroelectric capacitors (FeCAP’s). In this work the unusual electrical behavior of 3D FeCAP sidewalls was studied by comparing the electrical properties of two-dimensional and 3D integrated FeCAP structures. We evidenced composition variations of the SrBi2Ta2O9 (SBT) film in the sidewalls with marked bismuth segregation during metal-organic chemical-vapor deposition (MOCVD) of the SBT film. The segregation was reduced after decreasing the deposition temperature from 440°C, whereby the Bi-rich phase in the sidewalls does not contribute to polarization, down to 405°C, whereby sidewall SBT contributes to polarization. After further optimization of the MOCVD conditions at 405°C, the segregation is minimized and the ferroelectric contribution of the sidewall SBT is almost the same as the contribution of the planar SBT. As a result, 3D FeCAP’s integrated up to metal interconnection exhibit a remnant polarization Pr∼7.5μC∕cm2. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.2012508 |