Basic sputtering process and ferroelectric properties of single–domain single–crystal thin films of PbTiO₃

Abstract

Single c–domain single crystal PbTiO₃ (PT) thin films were prepared by sputtering on both miscut (001)SrTiO₃ (ST) and (110)SrRuO₃/miscut (001)ST substrates with a miscut angle of 1.7°. Film thickness ranged from 5 nm to 250 nm. The film growth was governed by step-flow growth and the film surface was atomically flat. The lattice misfit strain induced during the film growth was quenched. The PT films were tetragonally deformed and tightly bonded to the ST. The PT films showed no anomaly on the curves of lattice parameter in terms of temperature (temperature range, room temp. to 600°C), due to their excellent interfacial quality, although anomalies are expected at the Curie temperature (around 490°C in bulk PT). The P/E loops suggest that the saturation polarization P_s was 40 μC/cm² with a high coercive field of 400 to 500 kV/cm and a dielectric constant of 60 to 70 at 1 KHz. The P_s of the PT thin film is about half that of bulk PT.

Key Words:

• ferroelectric thin films
• PbTiO₃
• single domain