Low Power and Improved Switching Properties of Selector-Less Ta2O5 Based Resistive Random Access Memory Using Ti-Rich TiN Electrode

The effects of TiN top electrode composition (TiN vs Ti-rich TiN) on the resistive switching characteristics of selector-less TiN/TiOx/Ta2O5/TiN resistive random access memory (ReRAM) are investigated. Ti-rich TiN enables TiOx to have a higher concentration of oxygen vacancy and reduce barrier height between top electrode and TiOx. This leads to higher on/off current ratio and lower operation voltage without degradation of non-linearity which is the important factor for selector-less type ReRAM, compared to the stoichiometric TiN resistor stack. Consequently, it is verified that the switching mechanism is hybrid combination of filament formation and redox reaction in switching operation. This work is applicable to both high density and cost-effective ReRAM. (c) 2013 The Japan Society of Applied Physics