High on–off current ratio titanium oxynitride write-once-read-many-times memory

Abstract

In this letter, we demonstrate a titanium oxynitride (TiO x N y ) write-once-read-many-times memory with a high ON/OFF current ratio of 109. The endurance and read-disturb tests both reveal high stability and data nonvolatility of the TiO x N y resistive memory. A Ti metal layer was transformed into TiO x N y using an annealing process in a nitrogen ambient. The XPS analysis shows that the TiO x N y resistive switching (RS) layer possesses few Ti interstitial defects and oxygen deficiencies. A voltage-polarity dependent set process is observed in the Ag/TiO x N y /Ti/n+-Si resistive memory. The residual Ti metal layer provides a good contact with the TiO x N y RS layer, and the electrons can transport from the Ti to the Ag electrode via tunneling processes. In the low voltage region, the conduction current is dominated by the direct tunneling mechanism. When the voltage is beyond a transition voltage of 1.25 V, the carrier transport mechanism changes to Fowler–Nordheim tunneling. The conduction mechanisms are consistent with the finding obtained by the energy band diagram analysis.