Study On The Electrical Conduction Mechanism And Resistive Switching Properties Of Cu-bvased Titanium Oxide Electrolyte Structure

With the development of technology, memory becomes more and more necessary.Especially when the flash memory will reach its physical limitation. Among all of the nextgeneration memorys, resistive random access memory (RRAM) is one of the potentialcandidates due to its superior properties. Although it has been developed for several decades,the resistive switching (RS) mechanism is still not clear. In this thesis, we bring in some newRS theory based on TiOx.The electrodes in this thesis are evaporated by electron beam evaporation, while TiOxisdeposited by sputtering. The RS mechanisms are analysed by material propertiescharacterization mechods such as AES, AFM and Aglient B1500A.In this thesis, firstly, we discuss the current development of RRAM and its correspondingRS mechanisms. We made various the oxygen partial pressures and the distance betweentarget and substrate experiments, got a structure exhibiting multilevel resistive switchingproperty. Subsequently, based on the multilevel RS results, we propose the co-existence of Cuconductive filament (CF) and oxygen vacancy conductive filament (VO-CF) RS model whichis Cu-CF rupture followed by VO-CF.Secondly, we got forming-free, low power consumption and multilevel RS peroperties byimproving the experimental parameter.Thirdly, a thin SiO2layer was inserted between Al and TiOxlayer, showing lower powerconsumption property in Al/SiO2/TiOx/Cu structure compared to Al/TiOx/Cu. The function ofSiO2is avoiding the formation of VOregion by separate the Al layer and TiOxlayer to reducethe injection of electrons.Finally, the ionic switching is compared with electronic switching. By comparing theAl/TiOx/Al and Al/TiOx/Cu structure, the uniformity property of ionic switching type memoryis demonstrated.In this study, we analyzed the RS mechanism based on TiOxinsulator layer and proposed anew multilevel RS model. This study is good experience for low power, high density andhighly uniformity properties TiOx-based RRAM and it will contribute to the furtureapplication of RRAM.