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Material Science and Engineering
Sapphire (α-Al2O3) thin films can have applications as optical and scratch-resistant coatings, as well as in microelectronics. Typical sapphire substrate fabrication requires the material be in the molten state at temperatures above 2000°C. This study examines the crystallization of amorphous atomic layer deposited (ALD) alumina thin films at low temperatures (950-1050°C) by seeded lateral epitaxy. Decoration of the film with sapphire nanoparticle seeds before annealing provides nucleation sites for crystal growth. The growth rate of these grains was observed to be direction dependent according to the orientation of the nanoparticles. We also show the dependence of crystal growth rate on substrate thickness and stress state.
Maret, Hannah, "Seeded Lateral Epitaxy Rates for Alumina Thin Films: Influence of Substrate and Stress State" (2016). David and Lorraine Freed Undergraduate Research Symposium Winning Posters. 6.