Fabrication of Y doped BaZrO3 epitaxial film on YBa2Cu3Ox sacrificial buffer layer

• YBa2Cu3Ox buffers were proposed for Y doped BaZrO3 free standing films.
• Y doped BaZrO3 films were deposited on various substrates and orientation of the films was evaluated.
• Highly oriented Y doped BaZrO3 films were fabricated on YBa2Cu3Ox/YSZ/Si substrate.
• YBa2Cu3Ox buffers can be etched with fast rate without damaging Y doped BaZrO3 films.

Fabrication of highly oriented Y doped BaZrO3 (Ba(Zr,Y)O3:BZY) films on YBa2Cu3Ox (YBCO) sacrificial buffer layers was investigated. To clarify requirements of orientation control, BZY films were fabricated on various substrates using pulsed laser deposition (PLD). Cube-on-cube orientation relationship was obtained in BZY films on SrTiO3, LaAlO3, and MgO(100) regardless of PLD conditions, but orientation of BZY was strongly dependent on PLD conditions on yttria stabilized zirconia(YSZ) and CeO2(100), showing that perovskite structure or almost the same lattice parameter as BZY is needed to obtain cube-on-cube orientated BZY films. Cube-on-cube orientated BZY films were fabricated on YBCO, whose structure was perovskite, under wide ranging PLD conditions, showing that YBCO sufficiently controls crystalline orientation of BZY films. In addition, highly oriented BZY films were obtained on YBCO/YSZ/Si(100), demonstrating epitaxial BZY films on Si. Since good selective etching ability is also needed in sacrificial buffers, YBCO/BZY films were etched using H3PO4. H3PO4 etching removed the YBCO sacrificial buffers without damaging BZY with etching rate of ~ 30 nm/s. The present results show that YBCO sacrificial buffer layers are promising for fabrication of the μSOFCs with highly oriented BZY.