First-principles study of the conduction mechanism in tantala-based resistive memory devices

Herein, adopting the Pt/Ta2O5/Pt stack, first-principles calculations are carried out to investigate the conduction mechanism of tantala-based resistive switching devices. We first study the formation of conducting filament composed of the TaO2-x from the Ta2O5 matrix by modulating the number of oxygen vacancies and find that the TaO2-x filament formation is initiated from the metal contact through the redox reaction. Subsequent current-bias voltage characteristic analyses reveal that the Ta2O5 matrix with similar to 1.4 x 10(20) cm(-3) oxygen vacancy concentration assumes the low resistance state. It will be emphasized that the conduction mechanism behind the tantala-based resistive switching originates from the carrier concentration variation with the Schottky barrier height modulation according to the oxygen vacancy concentrations. The microscopic understanding accumulated in this study will provide an insight into the development of next-generation tantala-based resistive switching devices.