The initial stages of crystallization and growth of epitaxial Y-stabilized ZrO2 (YSZ) thin films on Si (001) substrates covered with amorphous native oxide were investigated by transmission electron microscopy (TEM) and reflection high-energy electron diffraction (RHEED). The YSZ crystallizes by solid-phase epitaxy with an initial thickness of 1 nm. The crystallization is initially incomplete, yielding both epitaxial and disordered regions of the YSZ film. In situ RHEED measurements showed the lattice parameter of the YSZ gradually decreased during growth, reaching the bulk value at a film thickness of 5–7 nm. For a larger thickness, the film is fully elastically relaxed. TEM revealed misfit dislocations at the YSZ/Si interface. The average spacing between misfit dislocations with Burgers vector b=1/2 〈110〉 was measured as 8.3 nm, showing epitaxial misfit strain to be fully accommodated by misfit dislocations. Thermal strain introduced during cooldown from the deposition temperature is fully elastically accommodated. For YSZ thicknesses below 7 nm, the thickness of the regrown layer of silicon oxide at the YSZ/Si interface is 0–0.5 nm.

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The interfaces of YBa2Cu3O7−δ (YBCO) thin films grown on Si substrates with Y-stabilized ZrO2 (YSZ) and Y2O3 buffer layers have been studied by high-resolution electron microscopy. At the Si-YSZ interfaces a 4-nm-thick amorphous silica layer is found, bridged by 10-nm-wide crystalline YSZ regions. Close to these regions the Si substrate contains planar {111} faults. At the YSZ-Y2O3 interfaces perfect misfit dislocations are present, with Burgers vector 1/2〈110〉. They occur either as separated single dislocations or as separated groups of closely spaced dislocations. The atomic coordination at the planar and atomically sharp Y2O3-YBCO interface could be revealed. The first atomic layer of the YBCO is found to be a Ba layer.