ABSTRACTThe oxygen conductor yttria-stabilized-zirconia (YSZ) is widely used in miniaturized solid oxide fuel cells (µSOFC) and may be suitable for solid state ion emitter applications e.g. as miniaturized ion engines for electric propulsion. Since the YSZ films are not completely free of stress during the growth, cracks in fabricated free-standing membranes are often observed.YSZ thin films were deposited on silicon substrates by radio frequency sputtering. Free-standing YSZ membranes were fabricated by partially removing the Si substrate by anisotropic wet-chemical etching using different masking patterns defined by electron beam lithography. We show how different sizes and etching conditions influence the strain in the fabricated membranes. To characterize these membranes we used optical microscopy and scanning electron microscopy.