Fabrication of Epitaxial Fe(3)O(4) Film on a Si(111) Substrate

The application of magnetic oxides in spintronics has recently attracted much attention. The epitaxial growth of magnetic oxide on Si could be the first step of new functional spintronics devices with semiconductors. However, epitaxial spinel ferrite films are generally grown on oxide substrates, not on semiconductors. To combine oxide spintronics and semiconductor technology, we fabricated Fe(3)O(4) films through epitaxial growth on a Si(111) substrate by inserting a γ-Al(2)O(3) buffer layer. Both of γ-Al(2)O(3) and Fe(3)O(4) layer grew epitaxially on Si and the films exhibited the magnetic and electronic properties as same as bulk. Furthermore, we also found the buffer layer dependence of crystal structure of Fe(3)O(4) by X-ray diffraction and high-resolution transmission electron microscope. The Fe(3)O(4) films on an amorphous-Al(2)O(3) buffer layer grown at room temperature grew uniaxially in the (111) orientation and had a textured structure in the plane. When Fe(3)O(4) was deposited on Si(111) directly, the poly-crystal Fe(3)O(4) films were obtained due to SiO(x) on Si substrate. The epitaxial Fe(3)O(4) layer on Si substrates enable us the integration of highly functional spintoronic devices with Si technology.