Mikrostruktur und Wachstum bei der ionenstrahlunterstützten Deposition von Yttrium-stabilisierten Zirkonoxid-Filmen

Abstract

In this work biaxially aligned yttria-stabilized zirconia (YSZ) films fabricated by ion-beam-assisted deposition (IBAD) at room temperature were studied by transmission electron microscopy (TEM) to provide a detailed describtion of the growth mechanism during the development of the biaxial texture. The TEM observations (cross-sectional and planar view) were compared with x-ray diffraction measurements (XRD).For the conventional production of biaxially aligned YSZ films the parameters of the assisting ion beam are of decisive meaning. To study the influence of the assisting ions during the film growth the films were deposited by different ion bombardment intensities. Additional bombardment experiments yield information about the ion doses.The growth of YSZ thin films produced by ion-beam-asssisted deposition can be considered as subdivided in different phases. The initial growth stage is characterized by an amorphous layer where the thickness decreases with increasing intensity of the assisting ion beam. The ion beam induced nucleation and the further film growth resulted in a prelimilary randomly orientated crystalline layer. A growth of existing nuclei as well as continuous and discontinuous changes of the orientation were observed in high resolution cross-section TEM. After the phase of growth selection the further growth is columnar.The results are discussed with different models which discribe the biaxial aligment by an oppression of misaligned grains.