Effect of platinum buffer layer on the fabrication process of flexible ferroelectric epitaxial thin films

Epitaxial thin films of a ferroelectric perovskite-type oxide grown on single-crystalline SrTiO₃ (100) were transferred onto a flexible printed circuit (FPC). In the case that the thin films were directly adhered onto FPC using a copper foil double-coated conductive adhesive tape (Cu double-sided tape), serious cracking and exfoliation occurred during the transfer process. To avoid these damages, we have tried to insert a metal buffer layer with excellent ductility between the ferroelectric oxide thin film and the Cu double-sided tape. The platinum buffer layer was found to be appropriate to establish a crack- and exfoliation-free transfer process.