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
${\rm Ge}/{\rm TaO}_{x}$
bilayer-based resistive switching devices, as compared with non-Ge devices. In addition, the reported
${\rm Ge}/{\rm TaO}_{x}$
devices also show significant reductions in the operation voltages. Influence of the Ge layer on the resistive switching of
${\rm TaO}_{x}$
-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
${\rm Ge}/{\rm TaO}_{x}$
devices.