Epitaxial ferroelectric (Pb, La)(Zr, Ti)O3 thin films on stainless steel by excimer laser liftoff

Epitaxial (Pb0.90La0.07)(Zr0.5Ti0.5)O3 (PLZT) films, 1.4 μm in thickness, have been transferred from their (100) MgO growth substrates to stainless-steel receptor substrates. The films on their MgO growth substrates were first attached to 25 μm stainless-steel shims using a transient-liquid-phase Pd–In bonding process, followed by irradiation through the MgO substrate with a single 248 nm excimer laser pulse. The 38 ns pulse at 400 mJ/cm2 fluence melted a thin layer of PLZT at the interface, expelling the MgO and leaving the PLZT film bonded to the stainless-steel receptor substrate. X-ray diffraction analysis of the PLZT films showed that the crystallographic structure of the film is maintained during laser liftoff. Scanning electron microscopy observations of the original interface reveal the presence of a thin quenched-liquid surface layer, as predicted by a thermal model of the process. Electrical testing of the films before and after laser liftoff demonstrated that the ferroelectric properties are retained by the transferred film.