Research On Anionic And Cationic Resistive Random Access Memory Based On Amorphous InGaZnO Thin Films

With the slowing down of Moore's law and the limitation brought by the Von Neumann bottleneck,traditional silicon-based memory is facing with serious physical size constraints caused by technological processes.Resistive random access memory has the advantages of simple structure,low power consumption,fast read and write speed,and high storage density,but its shortcomings in material optimization,performance stability and resistive switching principles also limit its development and applications.Amorphous In Ga Zn O films have the advantages of high electron mobility,adjustable oxygen defect,good mechanical flexibility and high transparency,which can be used in the thin film transistor and resistive random access memory.In this thesis,amorphous In Ga Zn O films were selected as the resistive switching dielectric layer,and the amorphous In Ga Zn O films were prepared by the sol-gel method.The surface roughness,chemical composition,surface morphology,optical transmittance and other properties of the prepared films were characterized and analyzed.Then,combining with the DC magnetron sputtering technology,anion migration and cation migration resistive random access memories were prepared.The resistive switching properties of the two types of devices were studied,and the resistive switching mechanism explanation was given in combination with the influence of electrode materials of the devices.Finally,the performance characteristics of anionic and cationic migration devices are compared.When Pt and Ti are used as the top electrode,the amorphous In Ga Zn O resistive random access memory exhibits anion migration type.The devices can show stable resistive switching performance at milliampere operating current.The storage window of both devices can be stabilized at more than 10 times,and they have good non-volatility(>10000 s)and repeatability(>100 times).By modulating the compliance current and the cut-off voltage of the reset process,a good multi-level storage capability can be obtained.In the cation mobility device,Ag/In Ga Zn O/Pt resistive random access memory can exhibit repeatable resistive switching behavior under different compliance currents(10^-3?10^-5 A).The device has a stable and reliable resistive switching performance when the compliance current is at 10^-5 A.,and the storage window of the device is always maintained at more than 500 times during 100 consecutive voltage sweeps and continuous voltage reading of 10000 s,and the distribution of resistance state and switching voltage of different devices are also concentrated.In addition,the operating current of memory is at the level of 10 microamps,which has obvious advantages of low power consumption compared with anion migration resistive memory devices.Moreover,the device also exhibits resistive switching performance at10^-6 A operating current,but the repeatability is poor.The resistive switching principle of both ion-migration types of resistive random access memory can be attributed to the formation and rupture of the conducting filament.In the anionic type,the electric field regulates the separation and migration of oxygen vacancy and oxygen ion to form an oxygen vacancy type conducting filament.For the cationic type,Ag electrode participates in the formation and rupture of Ag conductive filament in the form of Ag⁺.In this thesis,the anionic and cationic migration resistive random access memories based on amorphous In Ga Zn O thin films were studied,which provides an experimental reference for the reasonable selection of electrode materials of the resistive memory,the improvement of the resistive switching performance of devices,and the understanding of the resistive switching mechanism of amorphous In Ga Zn O resistive memory.