Effect of sputtering atmosphere on the characteristics of ZrO_x resistive switching memory

A ZrO_x switching layer with different oxygen content for TiN/ZrO_x/Pt resistive switching (RS) memory was prepared by magnetron sputtering in different atmospheres such as N₂/Ar mixture, O₂/Ar mixture as well as pure Ar. The morphology, structure and RS characteristics were systemically investigated and it was found that the RS performance is highly dependent on the sputtering atmosphere. For the memory device sputtered in N₂/Ar mixture, with 8.06% nitrogen content in the ZrO_x switching layer, the highest uniformity with smallest distribution of V _set and high resistance states (HRS)/low resistance states (LRS) values were achieved. By analyzing the current conduction mechanisms combined with possible RS mechanisms for three devices, we deduce that for the device with a ZrO_x layer sputtered in N₂/Ar mixture, oxygen ions (O²⁻), which are decisive to the disruption/formation of the conductive filament, will gather around the tip of the filament due to the existence of doping nitrogen, and lead to the reduction of O²⁻ migration randomness in the operation process, so that the uniformity of the N-doped ZrO_x device can be improved. (paper)