Native defects in Al2O3 and their impact on III-V/Al2O3 metal-oxide-semiconductor-based devices
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- J. R. Weber
- University of California 1 Department of Physics, , Santa Barbara, California 93106-9530, USA
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- A. Janotti
- University of California 2 Materials Department, , Santa Barbara, California 93106-5050, USA
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- C. G. Van de Walle
- University of California 2 Materials Department, , Santa Barbara, California 93106-5050, USA
説明
<jats:p>Al 2 O 3 is a promising material for use as a dielectric in metal-oxide-semiconductor devices based on III-V compound semiconductors. However, the presence of deep levels and fixed charge in the Al2O3 layer is still a concern, with native defects being a possible cause of traps, leakage, and fixed charge. We report hybrid density functional calculations for vacancies, self-interstitials, and antisites in Al2O3. The energetic positions of defect levels are discussed in terms of the calculated band alignment at the interface between the oxide and relevant III-V materials. We find that oxygen vacancies are the defects most likely to introduce gap levels that may induce border traps or leakage current in a gate stack. In addition, both self-interstitials and aluminum vacancies introduce fixed charge that leads to increased carrier scattering in the channel and shifts the threshold voltage of the device.</jats:p>
収録刊行物
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- Journal of Applied Physics
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Journal of Applied Physics 109 (3), 033715-, 2011-02-01
AIP Publishing