Fabrication And Characterizations Of Flexible Ferroelectric Tunneling Structure

Ferroelectric storage uses the spontaneous polarization direction of ferroelectric thin film to store two states of'0'and'1',which has the advantages of high density and low power consumption,and is a storage solution that has long been concerned in the field of non-volatile storage.In recent years,the quality of ferroelectric thin films has been greatly improved after the advancement of thin film preparation technology.Stable residual polarization can be obtained in nano-thick films,and it is significant for ferroelectric tunneling memory devices.At the same time,the popularity of personal portable electronic devices has prompted the development of electronic devices towards lighter,thinner and wearable flexible electronics.Low-power flexible storage devices have broad application prospects.Under this background,combining traditional ferroelectric tunnel junctions with flexible organic substrates to develop new flexible ferroelectric tunneling memory devices with good storage performance is expected to have important applications in wearable devices.In this paper,the Ba Ti O₃/Sr₃Al₂O₆/Sr Ti O₃ heterostructure was prepared by pulsed laser deposition technology.Combined with the wet film stripping process,the Ba Ti O₃film with a thickness of only 4.8 nm was stripped and transferred to the growth of3,4-ethylenedioxythiophene polystyrene?PEDOT:PSS?semiconductor electrode on the polyethylene terephthalate?PET?flexible substrate.Before and after the transfer the crystal structure and ferroelectric properties of Ba Ti O₃ film were systematically studied.Tthe resistive change controlled was obtained in Pt/Ba Ti O₃/PEDOT:PSS/PET tunneling structure by the polarization reversal of Ba Ti O₃.The main results are as follows:?1?The composite chemical Sr₃Al₂O₆ ceramic target was fabricated by solid-phase reaction method.The Ba Ti O₃/Sr₃Al₂O₆ heterostructure was successfully fabricated on the Ti-O single-termination?001?Sr Ti O₃ substrate after pre-etching treatment.X-ray diffraction results show that both Ba Ti O₃ and Sr₃Al₂O₆thin films crystallized well.?2?Using the water-soluble Sr₃Al₂O₆sacrificial layer and a wet stripping process,the epitaxial Ba Ti O₃ film with a thickness of only 4.8 nm was successfully stripped and transferred to a PET flexible substrate with a flexible electrode PEDOT:PSS.The transferred Ba Ti O₃ film maintains a single crystal structure and maintains good ferroelectric performance under different bending states.It is found that the coercive voltage of the Ba Ti O₃ film decreases with increasing curvature.?3?The I-V characteristics of the tunneling structure of Pt/Ba Ti O₃/PEDOT:PSS/PET were tested using a conductive atomic force probe Pt as the top electrode.Obvious tunneling induced resistance effect was observed,and the switching ratio was about 10.The barrier height of the tunneling structure was measured by X-ray photoelectron spectroscopy.It was found that the average barrier height was lower when Ba Ti O₃polarization pointed to PEDOT:PSS corresponding to the low resistance state,and the average barrier was higher when the polarization points to the Pt electrode,corresponding to high resistance state.