Microstructures in BaTiO 3 thin films by hydrothermal growth and lift-off technique

Abstract

Barium titanate microstructures with minimum feature sizes of 2.5 μm are fabricated on silicon substrates coated with platinum by a combination of hydrothermal growth and lift-off. Polycrystalline, cubic barium titanate is grown at a temperature of 80°C. Microstructures are obtained by positive and negative patterning processes, where the former leads to the better lift-off results due to the thicker resist layer. The minimum feature size of 2.5 μm refers to the minimum line width and separation between structures. It is limited by the optical lithography used in this work. The resolution of the pattern edges is estimated to be approximately 80 nm and would allow the fabrication of even smaller patterns. Additionally, it is shown that the use of electrochemistry for growth of thin barium titanate films is compatible with lift-off and leads to similar pattern definition.