Hetero-epitaxial Γ-Al₂O₃ on Si (100) substrate by sputtering

In this paper, the hetero-epitaxy of γ-Al₂O₃ films on Si (100) substrates by RF magnetron sputtering has been systematically studied. Crystal quality improves with growth temperature from 400 °C to 700 °C. The films sputtered with 4.5% extra O₂ or on a Si substrate with a thin oxide show better crystal qualities. Low sputtering power such as 60 W is essential to maintain good interfaces. Direct evidence of sputtering epitaxy of γ-Al₂O₃ on Si (100) is demonstrated for the first time. These results are very useful for low-cost growth of epitaxial γ-Al₂O₃ which has been used as buffer layers for epitaxial III-V materials on Si and barrier layers for electronic devices.