Improved Resistive Switching Behaviors Dependent On Pt/Ta₂O₅ Interfacial Change

Resistive random access memory,which is regarded as the next generation non-volatile memory,has attracted considerable attention due to its simple structure,low power consumption and outstanding device performance.Tantalum oxide is one of the prototype resistive switching materials due to the easy migration of oxygen ions by its low bonding energy.In traditional resistive switching models,people focus more on the Ta/Ta₂O₅interface,because oxygen vacancies created at the Ta/Ta₂O₅interface are the primary defects in the oxide.However,we found that the Pt/Ta₂O₅interface has the similar reaction during resistive switching process.And the optimization of Pt/Ta₂O₅interface could greatly improve the resistive switching behaviors.The contents of this thesis are:(1)By using a metal nanodots covered bottom electrode,the field distribution in the electrolyte layer is modified and the conductive filaments prefer to grow along the direction of Cu nanodots,leading to a microstructure change of the filament.Such simple and controllable filament structure contributes to the improved device stability.(2)By inserting an amorphous carbon layer at the Pt/Ta₂O₅interface,the positive-set and F8 switching mode phenomena disappeared.This means that oxygen vacancies created at Pt/Ta₂O₅interface were involved in the filaments growth.This discovery could enrich the physical model in Ta/Ta₂O₅/Pt structure.And carbon is a good blocking layer used to optimize the device performance.Based on the study of basic Ta/Ta₂O₅/Pt structure resistive switching behaviors,we propose two methods to modify the Pt/Ta₂O₅interface,and establish models to analyze the reasons for such huge improvements.This work provides a deep understanding of resistive switching mechanisms,and it is helpful to engineer further improvements in RRAM.