Fabrication and characterization of YSZ thin films for SOFC application

Abstract

Yttria stabilized zirconia (YSZ) thin films are deposited on thin Si₃N₄ layer coated Si substrates by RF-sputtering with different substrate temperatures, room temperature (YSZ-RT) and 550°C (YSZ-550). Fine polycrystalline structure is observed for YSZ-RT (thickness = 620 nm), while columnar crystal structure (111) oriented for YSZ-550 (thickness = 660 nm), respectively. The conductivity measurement shows that the activation energies of YSZ-RT and YSZ-550 are 1.34 and 1.58 eV, respectively, indicating that grain boundary conduction is dominant. Shear strengths of the YSZ films are determined by using a micro-blade cutting system to be 150 MPa for YSZ-RT and 200 MPa for TSZ-550, respectively. YSZ-550 is found to be better for solid oxide fuel cell application from mechanical and electrically properties point of view.