Microstructure and Surface Evolution in the Crystallization of α-Fe_2O_3/α-Al_2O_3(0001) Thin Films

摘要

We found the correlation between microstructure and surface evolution in the crystallization of amorphous α-Fe_2O_3/α-Al_2O_3(0001) thin films using real-time synchrotron x-ray scattering and atomic force microscope. The amorphous precursor is crystallized to the epitaxial α-Fe_2O_3 grains in three steps; ⅰ) the growth of the well aligned α-Fe_2O_3 interfacial islands on α-Al_2O_3(0001), ⅱ) the growth of the misaligned, homoepitaxial, α-Fe_2O_3 grains on the well aligned grains ( > 400℃), and ⅲ) the nucleation of the heteroepitaxial misaligned grains directly on the α-Al_2O_3 substrate ( > 600℃). The surface roughing is caused by the microstructure evolution during the crystallization of the amorphous precursor films.