High quality Sr1.8Ca0.2NaNb5O15/Li0.25Ni0.75O (SCNN/LNO) epitaxial heterostructures on (100) MgO substrates have been fabricated by pulsed laser deposition. X-ray diffraction analysis confirmed that the bilayer films possess an (001) orientation normal to the substrate surface. The LNO layer with smooth surface and good semiconductor behavior served as an ideal bottom electrode in the metal-insulator-semiconductor structure and an excellent template for epitaxial growth of SCNN thin film. Our results show that SCNN films with smoother surface, better (001) epitaxial orientation and better waveguide quality can be obtained by controlling the morphology of the LNO layer in a two-step deposition process. (C) 2015 Elsevier B.V. All rights reserved.