Initial growth stage of InTaO4 films deposited on MgO(0Â 0Â 1) substrates together with assisting O2-ion-beam by Ar-ion-beam sputtering of Ta target partly covered with In sheets

Thin-film growth process of InTaO4 on MgO substrates held at 700 °C is analyzed on the basis of the thickness dependence of the structure determined by X-ray diffraction analysis and the composition determined by X-ray photoemission spectroscopy. Monoclinic InTaO4 thin film grows at thicknesses above a critical value, while the amorphous phase grows at thicknesses below the critical thickness because the amount of In becomes insufficient to form the respective monoclinic structure. The In atoms are re-evaporated from the MgO surface at the initial growth stage. The growing films possibly comprise amorphous TaOx. The In atoms start to be incorporated into the growing films due to the reduction of re-evaporation of In atoms. This leads to the start of the interaction with Ta and O atoms resulting in the formation of InTaO4. The critical thickness to form a crystalline InTaO4 film is controlled by adjusting the incoming flux of In atoms.