Study On The Resistive Switching Performance And Mechanism Of Hafnium Oxide/Titanium Oxide Flexible Resistive Random Access Memory

At present,flexible wearable electronic devices are one of the important trends in the development of electronic devices in the future.People urgently need to develop a storage device based on flexible substrate,which can realize data storage,processing operation,radio frequency communication and other functions and be applied in the fields of flexible display,radio frequency identification,biomedicine and so on.However,as the most widely used non-volatile memory,silicon-based floating gate flash memory has disadvantages such as low write speed and high voltage during write operation.As one of the main candidates of the next generation non-volatile memory devices,new-generation memory devices,such as RRAM,have become a research hotspot at home and abroad.The principle and mechanism of binary transition metal oxide hafnium oxide/titanium oxide system applied in resistive memory are studied in this thesis.It was found that the light transmittance of the film was more than 94%.With rapid thermal annealing treatment at 400?and found that the membrane system as a new type of ferroelectric materials,with the rest of the polarization of 41?C/cm².In this thesis,the resistance characteristics of flexible hafnium/titanium oxide resistor memory are studied.It is found that hafnium oxide/titanium oxide flexible resistance memory has typical bipolar resistance characteristics and excellent resistance parameter consistency.By testing the bending resistance of the device,it is found that the high and low resistance Window of the device remains unchanged under different bending radii.By analyzing the fitting results of current conduction mechanism,the device is an ohmic mechanism at low resistance state and a schottky emission mechanism at high resistance state.In combination with the photoelectron spectroscopy(XPS)depth analysis of the device in the low resistance state,it is found that the oxygen vacancy content in the area near the upper and lower electrodes is significantly higher than that at the interface.Based on the analysis of electrical properties and material characterization,it can be inferred that the conductive filament of the resistor is disconnected at the interface of hafnium and titanium oxide,and the resistive layer of titanium oxide as a virtual electrode.This model can reasonably explain the excellent resistivity brought by the double-layer structure design and can be verified by XPS.The two-layer structure design of the device greatly improves the resistance parameter consistency.Lastly,the mechanism of hafnium oxide/titanium oxide flexible resistance storage device is studied.It was found that the high resistance state of the Hf O₂/Ti O₂ flexible resistance storage device decreased gradually and the low resistance state resistance value remained almost the same after 1000 cycles.The decrease of the high resistance state is due to the shorter shrinking distance of the conductive channel during the reset process.However,with the increase of reverse cut-off voltage,it is found that the device window has a tendency of recovery.It can be inferred that this is because after the increase of reverse cut-off voltage,more oxygen will participate in the reaction,leading to the gradual increase of the resistance value of high resistance state.In summary,this thesis studies the preparation and resistance performance of hafnium/titanium oxide flexible resistance storage device,obtains the resistance device unit with excellent resistance performance and studies the resistance mechanism.On the one hand,it provides a reliable experimental basis for the application research of flexible resistance memory devices with excellent performance;On the other hand,it has important scientific value for the discussion of the mechanism of binary oxide memory.