Characterization of Rf-Sputtered Lanthanum Aluminate Thin Films

Abstract

To obtain good quality superconducting thin films on conventional sapphire and silicon substrates we have investigated the deposition of buffer layers of lanthanum aluminate. The depositions were performed using rf-magnetron sputtering with a lanthanum aluminate target and a heated or rotating substrate holder. Energy-dispersive x-ray spectroscopy analysis showed that the stoichiometry of the films is correct and scanning electron microscopy analysis indicated good film morphology. X-ray diffraction analysis was used to determine the phase, purity, and degree of crystallinity of the buffer films both before and after annealing. We have been able to produce smooth amorphous and crystalline films of lanthanum aluminate with the correct stoichiometry on both sapphire and silicon and are currently working toward single crystal buffer layers with particular orientations.