Room-temperature epitaxial growth and in situ CAICISS surface analysis of wurtzite-type thin films

摘要

Low-temperature epitaxial growth of wurtzite-type thin films of ZnO and AlN was examined by laser molecular beam epitaxy (laser MBE), and the surface structure of these films was analyzed by in situ coaxial impact-collision ion scattering spectroscopy (CAICISS). We have achieved room-temperature (～20℃) epitaxial growths of ZnO films on NiO- or AlN-buffered sapphire(0001) substrates as well as A1N films on TiN-buffered sapphire(0001) substrates, while the ZnO films or AlN films were grown in the polycrystalline or amorphous phase on sapphire(0001) without any buffer layers at room temperature. From in situ CAICISS measurements, the deposited ZnO films were found to have +c polarity, that is, Zn-plane termination on the NiO- or AlN-buffered sapphire at room temperature. These room-temperature epitaxially grown films had the ultra-smooth surface, exhibiting atomic steps derived from the substrate.