In situ X-Ray Diffraction Studies of the Growing Thin Films of YSZ and GDC Using Synchrotron Radiation

In this paper, the formation process and time evolution of the crystal structure of thin films of yttriastabilized zirconia ZrO:YO (YSZ) and gadolinia-doped ceria CeGdO, (GDC) were investigated. YSZ and GDC films for use as an electrolyte layer in microtubular solid oxide fuel cells were formed by reactive mid-frequency magnetron sputtering on WC-Co alloy substrates. The films were deposited in a vacuum setup specially designed for in situ X-ray diffraction studies of thin film growth using synchrotron radiation. It is shown that the texture of the formed films is determined by the substrate temperature. At a substrate temperature of 100‒187°C, YSZ and GDC films with a cubic crystal lattice are formed. Under such deposition conditions, YSZ films have a preferred orientation of (200), whereas for GDC films the preferred orientation changes from (111) to (220) during growth. To obtain YSZ and GDC films with a preferred orientation (111), which have the highest ionic conductivity, it is necessary to increase the mobility of adsorbed atoms by increasing the substrate temperature or applying a bias voltage to it. It is also shown that with the deposition parameters used, compressive residual stresses are formed in both films, which decrease slightly in amplitude with increasing film thickness due to the increase in grain size.