Abstract
The structure of the interface produced by dry oxidation has been studied using positron annihilation spectroscopy using energy-variable slow positron beams. Based on the Doppler broadening shape and wing parameter () correlation, the interface layer was clearly distinguished from the and layers. A single positron lifetime of , which is sufficiently longer than that in the substrate and close to the second lifetime in the layer, was obtained when the incident positron energy was adjusted at the interface layer. The electron-positron momentum distribution associated with the interface layer was well explained by a theoretical calculation that considered the annihilation of the positrons by the oxygen valence electrons in the layer. The annealing process after the oxidation resulted in the modification of the electron-positron momentum distribution in a manner similar to that of the interface traps, thereby suggesting that the interface traps correlate with the positron annihilation site.
1 More- Received 13 June 2005
DOI:https://doi.org/10.1103/PhysRevB.73.014111
©2006 American Physical Society