Environmentally Friendly Microfabrication of Oxide Thin Films With Minimal Residue Using Water Lift‐Off Process With Sacrificial <i>a</i>‐CaO Layer

ABSTRACT The use of amorphous calcium oxide ( a ‐CaO) as a sacrificial layer to pattern lead zirconate titanate thin film on strontium titanate substrates using a water lift‐off process has been studied. The aim is to develop an environmentally friendly and residue‐free patterning method as an alternative to conventional chemical etching, which often causes damage, leaves contaminants, or generates hazardous waste. Atomic force microscopy (AFM) results demonstrate the structural stability of the a ‐CaO layer at high temperatures. Scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS) confirm minimal calcium residue on the patterned film and the substrate. XRD confirms PZT film grown epitaxially on the STO substrate, and no CaO is detected. These findings suggest that proving its effectiveness and sustainability for oxide thin film microfabrication. The results indicate minimal residue formation and high thermal stability of the sacrificial layer, demonstrating its effectiveness in oxide thin film microfabrication.