Research On Resistive Characteristic And Conductive Filament Regulation Of TaOx_based Memristor

The era of big data and intelligence age puts higher demands on the storage of data.Memristors with its excellent performance as high-speed,low power consumption,high integration and CMOS process compatibility,which can not only meet the requirements for next-generation memory applications,but also realize Analog In-memory Computing,must play a brilliant role on the information storage,Analog In-memory Computing,and the application of artificial neural components.The TaO_x memristor is one of the top candidates for next-generation memory and Analog In-memory Computing due to its excellent resistive performance.However,the shape,number,and the ruptured/connected position of the localized nano-conducting channels in the resistive switching process are extremely random.This intrinsic randomness of memristor leads to the variability of operating parameters and resistive characteristic,which cannot meet the requirements of industrialization.Therefore,it is of great significance to understand the resistive switching mechanism based on the oxygen vacancy conductive filament In order to realize the controllability of conductive filament with respect to its morphology,growth and the on-off region.In this paper,based on the analysis of the evolution process of oxygen vacancy conductive filament and the interface between electrode and function layer,a new memristor was developed by using an oxygen concentration gradient film.The characteristics of stability,variability,reduction of forming voltage and leakage current,low-voltage operation at high-speed,etc.are explored.The main research contents are as follows:?1?Study the self-limiting characteristics and the evolution of the nano-conducting channels of the device and the endurance degradation based on the memristive properties of TaO_x film with different oxygen content using reactive sputtering.The detailed researches were involved with the structure of the device,the preparation process,the substrate temperature,the film characteristics,the self-limiting mechanism with respect to the interface and the mechanism analysis of the endurance degradation.Finally,a model of the overgrowth of the conductive filaments after cycles based on multiple conductive filaments was proposed to illustrate the failure mechanism.?2?Design and preparation of oxygen gradient memristors.The ratio of O₂ to Ar in the magnetron sputtering process was adjusted to prepare an oxygen concentration gradient memristor whose oxygen content gradually increased from Ta electrode to Pt electrode.The microstructure and functional layer component of the device were studied by transmission electron microscopy.?3?Study on the resistive characteristics and mechanism of oxygen gradient memristor.By comparing the performance of memristor based on oxygen gradient and oxygen uniform film,it is found that the device based on oxygen gradient film can reduce the forming voltage,variability and suppress the leakage current.The pulse characteristic of low-voltage operation at high-speed over 10⁴ times?<1V/100ns,50ns;<3.3 V/10ns?was performed.According to the electrical characteristics of the device and the gradient distribution of the applied electric field and thermal conductivity across the device,a model of gradient-induced single conductive filament with conical shape,whose ruptured/connected region was localized,was proposed.