Effect of growth temperature on structural and morphological evolution of epitaxial SrTiO3 thin films grown on LaAlO3 (001) substrates by ion beam sputter deposition

• The SrTiO3 thin films were epitaxially grown on LaAlO3 (001) substrate by IBSD.
• Growth temperature has a strong influence on the evolution of crystal structure and growth mode.
• The STO thin films are under in-plane compressive strain with a tetragonal distortion.
• The transition from 3D island to 2D layer-by-layer growth mode occurs at ≥750 °C.

A series of epitaxial SrTiO3 (STO) thin films were grown on (001)-oriented LaAlO3 (LAO) substrates by ion beam sputter deposition (IBSD) at various growth temperatures in the range of 350–800 °C. Our results have shown that the growth temperature plays an essential role in influencing the structural and morphological evolution of the STO thin films. X-ray structural analysis demonstrates that the STO thin films are grown under in-plane compressive strain due to the effect of lattice mismatch. The out-of-plane lattice constant is found to decrease with increasing growth temperature. Atomic force microscopy observation reveals that the growth mode of STO thin films transforms from a three-dimensional island mode to a two-dimensional layer-by-layer mode at a sufficiently high growth temperature of 750 °C. We believe that high-quality epitaxial STO thin films with atomically flat surface prepared by IBSD in this study would be beneficial for the fabrication of perovskite STO-based superlattices.