Study On Resistive Switching Mechanism Of BaTiO₃/SmNiO₃ Heterojunction

Nowadays,"big data","cloud computing","artificial intelligence"and other key words have almost become the synonyms of today's scientific and technological development.Informatization and intellectualization already became future general trend.As a storage medium of information,memory plays an important role in integrated circuits.However,in the future,more and more information needs to be stored,but people's demand for device miniaturization is getting higher and higher,which means that the integrated circuit density must be greatly increased.However,the traditional memory technology has been unable to further shrink the device,which means that the traditional storage has been unable to keep up with the pace of future scientific and technological development,memory improvement or reform is imperative.Resistive random access memory?RRAMs?can not only meet the demand of technology development of device miniaturization,its good fault tolerance,the advantages of low power consumption are making it a good alternative to traditional storage.As an excellent member of RRAMs,ferroelectric RRAMs has good reliability and maintenance performance,which is widely welcomed by scientific researchers.In order to better understand and develop the ferroelectric RRAMs,their RS?resistive switching?mechanism must be understood.However,RS mechanism in ferroelectric materials is still controversial.In this paper,the RS mechanism of barium titanate?BaTiO₃?ferroelectric thin film is systematically studied.In order to obtain the appropriate bottom electrode,we firstly optimized the process of SNO?SmNiO₃?and found that the growth oxygen pressure of SNO had a great influence on the electrical properties of the Au/Cr/BTO?BaTiO₃?/SNO/LAO devices.We measured two completely different electrical properties in SNO devices with an oxygen pressure of3Pa.In one of the electrical properties,there is a very obvious jump process on the I-V curve,which we suspect may be related to the filament.In addition,in this kind of electrical characteristic,we also realize the transformation of the device's volatile-nonvolatile performance by adjusting the limiting current.In the other electrical characteristic,the current varies continuously with the voltage,and we infer that it is related to BTO according to the later experiments.At SNO oxygen pressure of 13Pa and 20Pa,the device showed good RS characteristics.Based on our optimization results for the oxygen pressure of SNO/LAO,we chose 13Pa SNO as the bottom electrode for the RS principle of BTO to be studied later.In order to determine the effect of ferroelectric polarization on RS characteristics,we controlled Ti/Ba ratio by changing oxygen pressure in the growth process of the film,so as to prepare ferroelectric and non-ferroelectric BTO films.Through measurement of piezoelectric force microscopy,it was confirmed that the film of BTO prepared under P_O2?3Pa has good ferroelectric property,while the film prepared under lower oxygen pressure disappeared.RS characteristics are obvious in heterogeneous junction with ferroelectric BTO,and the resistance ON/OFF ratio can reach 10⁴%,while RS can be ignored in heterogeneous junction with non-ferroelectric BTO.RS is highly dependent on ferroelectricity,because RS in BTO is generated by the regulation of ferroelectric polarization on BTO/SNO interface barrier and depletion region.