A strategy for fabricating micro-scale freestanding single-crystalline complex oxide device arrays

TL;DR

This paper introduces a versatile fabrication method for creating freestanding, single-crystalline complex oxide device arrays using wet etching and epitaxial lift-off, demonstrated with ferroelectric oxide systems.

Contribution

It presents a novel, general strategy for fabricating freestanding oxide device arrays, enabling their integration onto various substrates.

Findings

Successfully fabricated freestanding oxide device arrays.

Demonstrated heterogenous integration onto glass substrates.

Applicable to various complex oxide systems.

Abstract

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$_{0.2}$Ti$_{0.8}$)O$_3$-0.5Ba(Zr$_{0.7}$Ti$_{0.3}$)O$_3$ (BCZT) as a model relaxor ferroelectric oxide system and La$_{0.7}$Sr$_{0.3}$MnO$_3$ 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.