Processes heat conduction and diffusion in the effects resistive switching memory in thin-film oxide structures

PhD Irina Bute (Department of Information Measuring Systems and Physical Electronics/PetrSU) A resistive switching effect based on the simple binary metal oxideshas attracted considerable attention due to the possibility of its applicationin new electronic memory chips. Experimental data were analyzed bytransient electric thermal process of forming unipolar switching memorystructure Pt/NiO/Pt. Numerical simulations of the process shows that thechannel can be identified with melting of the nickel oxide region, wherein itscross section is determined by the maximum breakdown current, which is asignificant contribution to the parasitic capacitance can make. To form achannel parameter estimates are given analytical approximation. The transition process from the low resistance state into the highresistance state in a Pt/NiO/Pt memory switching structure has beenstudied by numerical modeling. Detailed analysis shows, that thermallyinduced diffusion oxidation by nickel vacancies is the key factor fordistortion of the channel metallic conductivity. Spatial dynamics of theprocess of oxidation defines channel narrowing mainly in its central part,and also sets the critical current through the structure sufficient for finalrupture of the channel and the transition to high resistance state. Theincrease in critical current above the limit even by 10% reduces theswitching time by an order of magnitude, which is in agreement withexperiments. The developed radial diffusion model of conductive channel (orfilaments) oxidation may be suitable for the analysis of switching effect anumber of other ReRAM oxide structures.