Understanding degradation and breakdown of SiO2 gate dielectric with “negative Hubbard U” dangling bonds
Degradation and time dependent breakdown of SiO2 gate oxides are discussed based on the Anderson–Mott theory of amorphous solids with dangling bonds as diamagnetic “negative Hubbard U” centers. Negative-U dangling bonds in the oxide are either positive D+ centers or two-electron negative D− centers....
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Veröffentlicht in: | Journal of applied physics 2004-03, Vol.95 (5), p.2490-2494 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | Degradation and time dependent breakdown of SiO2 gate oxides are discussed based on the Anderson–Mott theory of amorphous solids with dangling bonds as diamagnetic “negative Hubbard U” centers. Negative-U dangling bonds in the oxide are either positive D+ centers or two-electron negative D− centers. Due to a large difference in mobility between electrons and holes, hopping current in SiO2 is mainly electron current on D+ centers. Degradation of isolation properties and time dependent breakdown of SiO2 gate oxide under voltage stress are due to the conversion of D− into D+ centers caused by the hole-hopping current in SiO2. The reaction of conversion is stress polarity dependent. Thermal conductivity of Si is approximately 100 times higher than thermal conductivity of SiO2. Heat dissipation and accumulation of D+ centers inside the oxide are important in understanding the time dependent breakdown of the oxide. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.1643773 |