Interface structure of Pb(Zr,Ti)O3/MgO(001) epitaxial thin film in early stage of Stranski-Krastanov growth mode

• Published in: Japanese Journal of Applied Physics 2019-11, Vol.58 (SL), p.SLLA08
• Main Authors: Kiguchi, Takanori, Kodama, Yumiko, Shimizu, Takumi, Shiraishi, Takahisa, Wakiya, Naoki, Konno, Toyohiko J.
• Format: Article
• Language: English
• Subjects: Compressive properties; Crystal growth; Dislocation mobility; Epitaxial growth; Interface stability; Lead zirconate titanates; Magnesium oxide; Misfit dislocations; Modulation; Phase stability; Stacking faults; Thin films; Zirconium
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/1347-4065/ab3b13

This study investigated structural changes of Pb(Zr,Ti)O3/MgO(001) thin films prepared using MOCVD in the early stage of the Stranski-Krastanov growth mode. The strain state of the interface layer and the island region of PZT changes accompanied by a downward climb motion of misfit dislocations into the PZT/MgO interface with crystal growth. The local strain field around the misfit dislocation core formed in-plane compressive strain in the in-plane direction in the interface layer, which was strained tetragonally, but the island region had a pseudocubic structure. These results suggest that the residual strain induced phase stability modulation as well as Zr/Ti compositional gradient. A proposed model structure involves consequently dislocations with 〈110〉MgO slip on MgO can account for a stable interface without stacking fault. These results indicate the misfit strain-induced modulation of the interface structure and the phase stability in the early stage of the crystal growth on an atomic scale.