Defect Evaluation of O2-annealed TaOx for Transparent ReRAM with High Resistance Ratio $(R_{\mathrm{HRS}}/R_{\mathrm{LRS}}>10^{9}$

Annealing effects on the electrical resistance, the oxygen ratio to TaO
_x
, and fluorescence from the TaOx are examined for the development of the transparent Resistive- Random-Access-Memory (ReRAM). The O
₂
-annealing step inserted just after oxide-layer (TaO
_x
) deposition increases the electrical resistances of the ReRAM and the oxygen ratio evaluated by XPS. Time-resolved fluorescence showed that density of a defect level is reduced by the annealing. These results can be interpreted as decrease of oxygen vacancy (O
_v
) concentration and of leak-current through the Oc's. Fabrication results show that the Os-annealing can realize transparent ReRAM using ITO (Indium Tin Oxide) electrode with high resistance ratio (> 9 orders of magnitude) for low power application.