Heteroepitaxial growth of ZrO2-CeO2 thin films on Si (001) substrates

We have studied Zr1-xCexO2 film growth on (001) Si by Pulsed Laser Deposition using sputtering of metallic alloy targets and sintered ceramic targets. The conditions of the epitaxial growth have been found and optimized. The epitaxial oxide film growth (001)[100]parallel to(001)[100] Si was obtained for a range of CeO2 content in ZrO2: from 4.5 up to 14%mol in ZrO2. The oxide film structure corresponds to a tetragonal phase with strong preference for c-axis orientation normal to the growth surface. The results obtained by RHEED, XRD and AFM methods have confirmed the high quality of heteroepitaxial Zr1-xCexO2 layers, and the difference in crystallinities for the films grown from metallic alloy targets and ceramic targets was evaluated. The XRD results show the absence of any reflection distinct from (001) and (100) for films grown from alloy targets, and, in contrast with this, the film structure contains some random oriented inclusions in the case of oxide target deposition. Use of metallic alloy Zr-12%Ce targets and low oxygen pressure during deposition provide the best film quality with the minimum of surface microrelief (Rrms < 0.3 nm for 1 x 1 mu m(2) surface area was achieved).