Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8035196 | Thin Solid Films | 2014 | 6 Pages |
Abstract
For formation of gate dielectrics with higher permittivity (higher-k) using rare-earth oxide thin film, we have investigated the effect of H2O partial pressure (PH2O) during the Pr-oxide film formation and annealing on the Pr valence states and the amorphous and crystalline phase structures of the Pr-oxide films. The amorphous structure of Pr-oxide is dominantly formed in the film formed by metal-organic chemical vapor deposition (MOCVD) at a low temperature of 300 °C. The decrease in PH2O during MOCVD leads to the formation of Pr2O3 (Pr3 +) composition compared with PrO2 (Pr4 +) composition. It achieves the increase in the permittivity of the Pr-oxide films. The PH2O value drastically changes the grain size of crystal Pr-oxide in the amorphous film, and the crystalline structure is identified to be hexagonal Pr2O3 without depending on the Pr-oxide composition in the amorphous region. The annealing of the Pr2O3 film in vacuum at 500 °C promotes the crystallization of the hexagonal Pr2O3 phase, although the annealing in N2 ambient forms cubic Pr2O3 phase.
Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Kimihiko Kato, Mitsuo Sakashita, Wakana Takeuchi, Noriyuki Taoka, Osamu Nakatsuka, Shigeaki Zaima,