Impact of roughness of TiN bottom electrode on the forming voltage of HfO2 based resistive memories

In this work, we study the impact of roughness of TiN bottom electrode on the forming voltage of 1R TiN/HfO2/Ti/TiN based ReRAM devices. A novel and atypical strategy is proposed to induce a controlled roughness of the bottom electrode, using various plasma chemistries. The forming voltage is observed to be directly linked to the roughness of the bottom electrode, over a large range of roughness values. TCAD simulation studies enable an estimate of the electrical field in the oxide inducing the forming step and confirm the dominant impact of roughness on the switching properties of ReRAM devices.