Structural and microstructural analyses of crystalline Er(2)O(3) high-k films grown on Si (001) by laser molecular beam epitaxy

Abstract Erbium oxide (Er 2 O 3 ) films are well regarded as being suited for high- k replacement of SiO 2 in endeavors to further miniaturize and enhance the performance of microelectronics. Er 2 O 3 films were deposited on Si (0 0 1) substrates by laser molecular beam epitaxy. The structures and microstructures of the films and the interfacial layers were characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results from the XRD and selected area electron diffractions of Er 2 O 3 films with thicknesses of 30 and 100 nm indicate that the films are polycrystalline, with dominant (1 1 1) textures of Er 2 O 3 {1 1 1} // Si (0 0 1). Amorphous layers dotted with small ordered islands were observed and confirmed to be located at the interfaces between the films and the Si substrates with dark-field image and high-resolution TEM. High-resolution Z-contrast imaging, energy dispersive X-ray spectroscopy and energy-filtered imaging were applied to identify the compositions of the interfacial layers. The salient feature is that the layers consist primarily of Er and O, with a very small amount of Si. This kind of Er–O-based interface layer may play a very important role in the electrical and optical properties of the films.