Fabrication and characterization of ferroelectric multilayered films fabricated by using solvent blending

Multilayer formation of thin films is indispensable for solution-based flexible devices because the structures of electronic devices such as transistors, diodes, capacitors and resistors include vertically layered thin films for operation at low voltage with a fast response. However, a solutionbased material can be affected by exposure to organic solvents, meaning that multilayer formation is very sensitive to the solvent used during the formation of an additionally deposited film. In this paper, a multilayer formation method with a ferroelectric polymer is suggested. The principle of this method is the control of the solubility of the polymer solution through the mixing of two types of solvents with different dipole moment values. After the multilayer had been formed, the polymer film was characterized by using polarization-voltage measurements. By fitting with a hyperbolic tangent function, we extracted the main parameters. In conclusion, a solubility modification in solvent is very useful for forming a solution-based multilayer for flexible, ferroelectric, nonvolatile memory applications.