Investigation On The Dynamics Of Conducting Filament In Resistive Switching Oxide

The non-volatile memory based on resistive switching?RS?,with its simple structure,high density,low power consumption,excellent endurance,fast reading and writing,compatible with CMOS technology and good expansibility is regarded as the most promising candidate for next generation nonvolatile memory,caused a lot of attention in academia and industry.However,there is a wide debate about the physical mechanism of RS.The RS effect is divided into interface type and channel type.People utilize electronic microscope,energy spectrum analysis,spectroscopy analysis,morphological analysis etc to investigate the RS effect of channel type,which confirm the existence of conducting filament?CF?and investigate the composition of CF.However,due to the filaments buried between metallic electrodes,the RS effect occurring in nano-sized region and complex ion migration dynamics etc,some key scientific questions about CF in RS effect are still not clear,such as,the dynamics process of the formation and rupture of CF,the change of structure and composition of CF during RS process etc.Aiming at those problems mentioned above,we nondestructively investigated the dynamics behavior of CF in resistive switching oxide in situ by electroluminescence?EL?in this thesis,including unipolar resistive switching?URS?Pt/NiO/Pt structure and bipolar resistive switching?BRS?ITO/TiO₂/ITO/Au structure,The main contents are listed as follows:?1?We fabricated the Pt/NiO/Pt structure with reversible URS.We have nondestructively observed the dynamic evolution of CFs across the device by EL,and demonstrate that both the random distribution and the subtle change in the chemical composition of CFs contribute to fluctuation of switching parameters;The EL emission during RS is attributed to the radiative transition through oxygen vacancy related defect levels of NiO rather than from the thermal radiation.We revealed the transition process of compound composition in RS region of CF during RS,found that the structure and composition of RS region in CF change continuously after the formation of CF.We confirmed that the RS effect occurs on the anode side of CF.?2?We fabricated the ITO/TiO₂/ITO/Au structure with reversible BRS.We investigated the transport mechanism of carriers and the dynamic evolution of CFs across the device during RS by EL,found that the random distribution of CFs under different voltage polarity contributes to unstable RS effect;We revealed that the transition process of compound composition of CF during RS,and found the stable component of RS region in CF.We found that temperature can change the structure and composition of CF,and confirmed that the BRS effect occurs on the cathode side of CF.?3?We investigated the RS characteristics of bipolar ITO/Cu₃N/ITO/Au structure,and observed anomalous RS effect.We improved RS performance of sample by improved preparation process.We investigated the EL behaviors from CF by EL during RS in unipolar Pt/ZnO/Pt structure,found that the formation and rupture of CF results in the transformation between high resistance state and low resistance state.