Highly stable, solution-processed quaternary oxide thin film-based resistive switching random access memory devices via global and local stoichiometric manipulation strategy.

Optimization and performance enhancement of a low-cost, solution-processed InGaZnO (IGZO) resistance random access memory (ReRAM) device using the manipulation of global and local oxygen vacancy (V) stoichiometry in metal oxide thin films was demonstrated. Control of the overall Ga composition within the IGZO thin film reduced the excessive formation of oxygen vacancies allowing for a reproducible resistance switching mechanism. Furthermore, sophisticated local control of stoichiometric V is achieved using a 5 nm Ni layer at the IGZO interface to serve as an oxygen capturing layer through the formation of NiO, consequently facilitating the formation of conductive filaments (CFs) and preventing abrupt degradation of device performance. Additionally, reducing the cell dimension of the IGZO-based ReRAMs using a cross-bar electrode structure appeared to drastically improve their performances parameters, including operating voltage and resistance distribution due to the suppression of excessive CFs formation. The optimized ReRAM devices exhibited stable unipolar resistive switching behavior with an endurance of >200 cycles, a retention time of 10 s at 85 °C and an on/off ratio greater than about 10. Therefore, our findings address the demand for low-cost memory devices with high stability and endurance for next-generation data storage technology.