Preparation And Properties Of Tantalum Oxide Multilayer Memristor By Magnetron Sputtering

With the rapid development of information technology,especially the continuous innovation in the fields of big data,cloud computing,Internet of Things and artificial intelligence,higher requirements are put forward for data collection,transmission,storage and processing.Traditional memory devices such as DRAM and flash memory can not meet these requirements,and new memory devices are needed to meet people’s needs for storage capacity and read and write speed.Compared with traditional memory devices,memristors have many advantages,such as fast response,high density and resetting,etc.These advantages make memristors become a very promising memory device,and because of its unique resistance characteristics and memory functions,it is expected to bring new breakthroughs for the research of larger capacity storage devices and more efficient information processing systems.Tantalum oxide material has the advantages of good thermal stability and high dielectric constant,and has been the research focus of resistive materials in recent years.Tantalum oxide film has excellent fatigue resistance and can maintain its stable storage state after millions of write and erase operations.In addition,tantalum oxide film also has a high resistivity effect and low power consumption,which can help achieve higher storage density and faster read and write speed.In this paper,tantalum oxide memristors with different structures are designed and prepared,and the effects of buffer layer,top electrode material,dielectric layer thickness and structure on the electrical properties of tantalum oxide memristors are studied.The main research work is as follows:（1）A sandwich structure memristor based on tantalum oxide film was prepared by reactive magnetron sputtering.ITO films with different orientations were prepared on Si substrate by changing the oxygen partial pressure.The effect of ITO films on the electrical properties of TaO_xsingle-layer memristor was studied.（2）In order to further improve the performance of TaO_x single-layer memristor,a TaO_x/ITO/ZnO device was prepared by adding ZnO thin film as the buffer layer.The test results show that ZnO film as the buffer layer promotes the crystallization effect of TaO_x film,and the resistance performance of the device is better than that of TaO_x/ITO structure.The effect of the top electrode materials（Ta,Au,Ti）on the structure is studied.It is found that the Ta top electrode device has the lowest switching voltage and power consumption,the best fatigue resistance and time retention characteristics,and the conduction mechanism of the device is analyzed（3）Based on Ta/TaO_x/ITO/ZnO devices,a Ta/ZnO/TaO_x/ITO/ZnO double-layer memristor was further prepared.The effect of ZnO and TaO_x thin film thickness on the device performance was studied,and the optimal thin film thickness of the double-layer memristor was determined.Different from the conduction mechanism of TaO_x single-layer devices,ZnO/TaO_x devices are mainly based on the coupling between the oxygen vacancy filaments in the ZnO layer and the Ta⁵⁺conductive filaments in the TaO_x layer,as well as the conduction mechanism of SCLC.