Thickness Dependence of the Crystallization of α-Fe₂O₃/α-Al₂O₃(0001) Thin Films Grown by Sputtering

Abstract:

The crystallization of α-Fe2O3/α-Al2O3(0001) thin films has been studied using real-time synchrotron x-ray scattering and atomic force microscope. In the sputter-grown amorphous films of various thicknesses at room temperature, we find the coexistence of α-Fe2O3 and Fe3O4 interfacial crystallites (~50-Å-thick), well aligned to the α-Al2O3[0001] direction. The amorphous precursor is crystallized to the epitaxial α-Fe2O3 grains in three steps with annealing temperature; i) the growth of the well aligned α-Fe2O3 interfacial crystallites to approximately 200-Å-thick, together with the transformation of the Fe3O4 crystallites to the α-Fe2O3 crystallites (< 400°C), ii) the growth of the less aligned α-Fe2O3 grains on top of the well aligned grains (> 400°C), and iii) the nucleation of the different less aligned α-Fe2O3 grains directly on the α-Al2O3 substrate (> 600°C). The surface evolution of the amorphous precursor films after annealing is consistent with the microstructure evolution during the crystallization.

• Periodical: Solid State Phenomena (Volumes 124-126)
• Pages: 1213-1216
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.124-126.1213
• Online since: June 2007
• Authors: Tae Sik Cho, Min Su Yi, Do Young Noh, Seok Joo Doh, Jung Ho Je
• Keywords: Crystallization, Sputtering, Thickness Dependence, α-Fe₂O₃/α-Al₂O₃(0001) Films

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