A Facile Vector Substrate Platform via BaTiO ₃ Membrane Transfer Enables High‐Quality Solution‐Processed Epitaxial PZT on Silicon

Abstract The direct integration of high‐performance ferroelectric oxides with silicon remains challenging due to lattice mismatch, thermal incompatibility, and the need for high‐temperature epitaxial growth. Here, a hybrid integration approach is demonstrated in which crystalline BaTiO ₃ (BTO) membranes are first transferred onto Pt‐coated Si substrates and subsequently used as vector substrates (VS) for the growth of epitaxial (001) Pb(Zr _0.52 Ti _0.48 )O ₃ (PZT) thin films via chemical solution deposition (CSD). A KI + HCl based etchant enables rapid and complete dissolution of the SrVO ₃ sacrificial layer in ≈30 min, reducing the release time from days to minutes compared with conventional water‐based approaches to dissolve AVO ₃ /AMoO ₃ (A = Ca, Sr, Ba). The BTO VS imposes dominant (00l) out‐of‐plane orientation and in‐plane cube‐on‐cube epitaxy in the overlying PZT. Devices exhibit P _r ≈ 10–12 µC cm ⁻² and E _C ≈ 100 kV cm ⁻¹ , with stable switching to 10⁸ cycles on the VS. From piezoelectric butterfly loops, the study extracts ​ ≈ 70 pm V ⁻¹ for PZT on VS and ≈54 pm V ⁻¹ for PZT grown on conventional Pt‐Si substrates. The approach establishes a general pathway for transferring crystalline oxides to any arbitrary substrate and employing them as vector substrates for epitaxial integration of functional oxides.