Interface reactions of high-κ Y2O3 gate oxides with Si
- 8 October 2001
- journal article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 79 (15) , 2447-2449
- https://doi.org/10.1063/1.1406989
Abstract
Ultrathin Y2O3 films were electron beam evaporated in an ultrahigh vacuum onto Si(100) and investigated by high-resolution medium energy ion scattering. Selected films were capped in situ with amorphous Si. Uncapped films that were exposed to air prior to analysis contained excess oxygen compared to a stoichiometric Y2O3 film, and showed a 6–8 Å interfacial layer. Si uptake from the substrate occurred in these films after a 700 °C vacuum anneal, presumably by reacting with the excess oxygen. Si-capped Y2O3 films on the other hand were stoichiometric, and the substrate interface was sharp (⩽2 Å), even after 900 °C vacuum anneals. No change was seen at the Y2O3 capping layer interface until ⩾800 °C for vacuum anneals. These measurements indicate that control of the interface composition is not possible after exposure of ultrathin Y2O3 films to air.Keywords
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