Improved Switching Uniformity and Low-Voltage Operation in ${\rm TaO}_{x}$ -Based RRAM Using Ge Reactive Layer

Significant improvements in the spatial and temporal uniformities of device switching parameters are successfully demonstrated in Ge/TaO_x bilayer-based resistive switching devices, as compared with non-Ge devices. In addition, the reported Ge/TaO_x devices also show significant reductions in the operation voltages. Influence of the Ge layer on the resistive switching of TaO_x-based resistive random access memory is investigated by X-ray spectroscopy and the theory of Gibbs free energy. Higher uniformity is attributed to the confinement of the filamentary switching process. The presence of a larger number of interface traps, which will create a beneficial electric field to facilitate the drift of oxygen vacancies, is believed to be responsible for the lower operation voltages in the Ge/TaO_x devices.