High-quality epitaxial growth of {gamma}-alumina films on {alpha}-alumina sapphire induced by ion-beam bombardment
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
We report the formation of epitaxial {gamma}-alumina thin films on {alpha}-alumina substrates induced by ion-beam bombardment. Single-crystal (0001) {alpha}-alumina was coated with 70-nm amorphous-alumina thin films and then bombarded with either 360-keV argon ions or 180-keV oxygen ions at 400, 500, and 600 {degree}C. Ion-channeling measurements showed a consistent minimum yield of 50% for the aluminum in the grown films. Cross-sectional transmission-electron microscopy revealed the formation of {gamma}-alumina epitaxially grown onto {alpha}-alumina with an orientation relationship [1{bar 1}0](111){gamma}{parallel}[01{bar 1}0](0001){alpha}. The epitaxy of {gamma}-alumina was further confirmed by x-ray-diffraction {phi} scans. This study indicates that ion-beam bombardment at 400--600 {degree}C not only induces the amorphous-to-{gamma} phase transformation but also effectively eliminates {l_brace}111{r_brace} twins of {gamma}-alumina, which are normally observed after thermal annealing at 800--900 {degree}C.
- OSTI ID:
- 147812
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 24 Vol. 52; ISSN 0163-1829; ISSN PRBMDO
- Country of Publication:
- United States
- Language:
- English
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