A Strategy for Fabricating Micro-Scale Freestanding Single-Crystalline Complex Oxide Device Arrays

We present a general fabrication strategy for freestanding single-crystalline complex oxide device arrays via wet chemical etching-based microfabrication processes and epitaxial lift-off. Here, we used 0.5Ba(Zr_0.2Ti_0.8)O_3-0.5Ba(Zr_0.7Ti_0.3)O_3 (BCZT) as a model relaxor ferroelectric oxide system and La_0.7Sr_0.3MnO_3 as the sacrificial layer for demonstration. Arrays of SrRuO_3 (SRO) / BCZT / SRO ferroelectric capacitor mesas were first defined and isolated on the growth wafer, and then they were released using epitaxial lift-off with lithography-defined surrounding etching holes, after which the freestanding device arrays were integrated onto a glass substrate. Our proposed strategy sheds light on preparing various freestanding single-crystalline oxide devices and paves the way for their heterogeneous integration onto arbitrary substates.