Growth Aspects of Thin-Film Composite Heterostructures of Oxide Multicomponent Perovskites for Electronics

We review, based on our results, the problems and solutions for the growth of thin films and composite heterostructures emphasizing the general growth aspects and principles vs specifics for each material or heterostructure. The materials used in our examples are Bi 2 Sr 2 Ca 2 Cu 3 O 10 , Bi 2 Sr 2 CaCu 2 O 8 , YBa 2 Cu 3 O 7 , (Sr, Ca)CuO 2 , (Ba, Ca)CuO 2 , and Bi 4 Ti 3 O 12 . The growth method was metal organic chemical vapor deposition (MOCVD). The presented thin films or heterostructures have $c$- and non-$c$-axis orientations. We discuss the implications of the film--substrate lattice relationships, paying attention to film--substrate lattice mismatch anisotropy and to film--film lattice mismatch, which has a significant influence on the quality of the non-$c$-axis heterostructures. We also present growth control through the use of vicinal substrates and two-temperature (template) and interrupted growth routes allowing significant quality improvements or optimization. Other key aspects of the growth mechanism, that is, roughness, morphology, and interdiffusion, are addressed. It is concluded that the requirements for the growth of non-$c$-axis heterostructures are more severe than those for the $c$-axis ones.