Fabricating electrolyte with thin film is one of various methods of lowering the operation temperature for solid oxide fuel cell (SOFC). Because the major polarization of SOFCs is ohmic loss, many groups have tried to fabricate a thin film electrolyte – some proton conducting material that has the conductivity of a couple of orders higher than oxygen conducting one. We have investigated the synthesis of Membrane Electrode Assembly (MEA) including Yttria-doped Barium Zirconate(BYZ) thin film electrolyte via thin-film processes such as Pulsed Laser Deposition and Sputtering. Another approach to lower the operation temperature of SOFCs is the bi-layer structure electrolyte. The functional layer via thin film deposition could guarantee minimum power density loss and stable operation. After the study of Atomic Layer Deposition (ALD) condition to deposit Yttria Stabilized Zirconia (YSZ) on Gadonilia doped Cerate (GDC) substrate, GDC/YSZ bi-layered electrolyte button cells showed higher OCV and larger limiting current with 100nm YSZ ultra thin film. The performance improvement might be attributed to the function of electron blocking and cutting off the reducible gas.