Doping effects on the kinetics of solid-phase epitaxial growth of amorphous alumina thin films on sapphire
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
The effects of doping on the kinetics of solid-phase epitaxial growth of amorphous alumina have been studied. Amorphous alumina ({ital Al}{sub 2}{ital O}{sub 3}) thin films, 200-265 mm thick, were deposited on to (0001) sapphire substrates by electron-beam evaporation. Iron or chromium atoms were uniformly doped into the films during deposition to cation concentrations below 5 cationic %. The kinetics of the epitaxial growth were studied at 800--1050 {degree}C in flowing oxygen gas by {ital in} {ital situ} time-resolved reflectivity techniques as well as by ion backscattering and channeling techniques. A phase transformation sequence from amorphous through gamma to alpha alumina has been observed in all the undoped and doped films. The transformation from {gamma} to {alpha} alumina is a thermally activated process with an activation energy of 5.0{plus_minus}0.2 eV, independent of the presence of dopants. However, the presence of dopants affects the overall transformation rate. Fe enhances while Cr slows the growth rate relative to the undoped case. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
- OSTI ID:
- 102343
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 7 Vol. 67; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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