Patent ID: 7238388

Claim:
A method for forming a ferroelectric thin film comprising: (a) dissolving a Pb precursor in a solvent to prepare a Pb precursor solution; (b) stabilizing a Zr precursor and a Ti precursor to prepare a Zr precursor solution and a Ti precursor solution; (c) mixing the Pb precursor solution of (a) with the Zr precursor solution and the Ti precursor solution of (b) to obtain a mixture of the Pb precursor solution, the Zr precursor solution, and the Ti precursor solution; (d) dissolving a Bi precursor in a ligand-substitution solvent selected from the group consisting of a C 1 -C 10 alcohol, a C 1-10 alkoxyalcohol, and mixtures thereof, and refluxing the resultant solution to prepare a Bi precursor solution; (e) dissolving a Si precursor in a solvent to prepare a Si precursor solution and mixing the Si precursor solution with the Bi precursor solution of (d) to obtain a mixture of the Bi precursor solution and the Si precursor solution, without hydrolyzing the mixture of the Bi precursor solution and the Si precursor solution; (f) mixing the unhydrolyzed mixture of the Bi precursor solution and the Si precursor solution of (e) with the mixture of the Pb precursor solution, the Zr precursor solution, and the Ti precursor solution of (c), and then hydrolyzing the resultant to obtain a composition for forming a ferroelectric thin film; and (g) coating the composition of (f) on a substrate and heating the coated film.