| The rapid development of information technology in the world cannot leave the nonvolatile memorycontinuously improve performance. In order to obtain more excellent performance of new type memory, alarge number of researchers are looking for a substitute for conventional memory. In this research area, wefound variety of oxide material have resistance switch phenomenon, most of the material have the potentialapplications for nonvolatile memory. Most of the traditional mechanism of nonvolatile memory can bedivided into two categories, one kind is ion mechanism, the other is electronic mechanism, compared withthe ion mechanism, the electronic mechanism usually to explain the resistance switch. However, the defectis closely related to resistive switching and difficult to control, Thus the conventional resistive switchingmemory has not got a great success in the commercialization. At this time, the ferroelectric materials intoour field of vision. barium titanate (BTO) thin films have attracted considerable attention as a typicalferroelectric, which have potential applications for next-generation nonvolatile memory and multifunctionaldevices. A lot of interesting phenomena have been observed in the electronic transport behaviors of BTOthin films, such as switchable diode effect, Ohmic to Schottky transition, bipolar resistive switching,magnetoelectric coupling, ferroeletric polarization switching on silicon without conducting bottomelectrode. Generally, the negative differential resistance (NDR) characteristic has been found to accompanywith resistive switching or not, which appears in other material system, such as double quantum wells,superlattices, and one-dimensional systems. As For the micro-mechanism of NDR, there is a great deal ofdisagreement. Various driving mechanisms including electro-migration of oxygen ions, charge trapping,filamentary conducting, have been suggested to understand the resistance switching, which are difficult toexplain the NDR accompanying with resistive switching. In previous reports, the NDR is rarely reported inBTO thin films.The ferroelectric material of barium titanate (BaTiO3) is a very typical ferroelectric material. Usinglaser pulse deposition technology, in the condition of different oxygen pressure conductive glass (FTO)substrate on growth barium titanate (BTO) ferroelectric thin film. XRD theta. Theta-2scans show in a better quality of substrate to grow out of the FTO BTO ferroelectric thin films, by sputtering process onBTO surface plating electrode diameter is0.001mm, the preparation of the Au/BTO/FTO device. After thedevice is to make use of Keithley2400I-V scanning, during the scanning process, has negative voltagearea will have a negative differential resistance showed with the increase of positive voltage. In order tofind out the negative differential resistance phenomenon and the cause of the phenomenon and the positivevoltage maintained a what kind of relationship, so we in the Au/BTO/FTO device has carried on theferroelectric properties, DLTS and and use its own building pulse test instrument on the device underdifferent positive and negative pulse negative differential resistance changes in the study, the observed, thedevices of the negative differential resistance phenomenon in different pulse width and pulse strength areaffected. The introduction of mechanisms to explain this device interface state resistance change switchphenomenon and the negative differential resistance phenomenon, use of Au/BTO type interface betweendonor interface state to the electron capture and explained the phenomenon to capture model perfect. Placesdifferent sizes on the tests give the device of positive bias, found that the resistance will be correspondingpresents a continuous variation trend. Show that the device also has as a multistage resistance change ofstorage potential. At the same time, the sample in low temperature environment, use of Keithley2400I-Vtest, found that under the condition of the low temperature environment, the Au/BTO/FTO appearedrectifier characteristics inversion phenomenon. And after tests showed that this kind of phenomenon is notreversible. Analysis it is concluded that the phenomenon is and is closely related to the Curie temperatureof the ferroelectric itself. In low temperature environment, due to the temperature reached the Curietemperature, so the BTO film crystal structure change were found. So will appear in low temperatureenvironment rectification characteristics inversion phenomenon. |
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