Impact of roughness of bottom electrodes on the resistive switching properties of platinum/nickel nitride/nickel 1 × 1 crossbar array resistive random access memory cells

In this study, we investigate the effect of the roughness height of bottom electrodes (BEs) on the resistive switching properties of a 1 × 1 platinum/nickel nitride/nickel (Pt/NiN/Ni) capacitor crossbar array (CBA) resistive random access memory (ReRAM) cell. The thickness of the rough surface is varied from 40 nm to 80 nm. In the resistive switching tests, the set voltage in the current-voltage (I-V) curves is reduced by using a rough surface (RS) BE in the Si wafer, and the reset current is reduced by increasing the surface roughness height of the Si wafer. On the other hand, there is a reduction in V_SET/RESET and I_SET/RESET variations in the I-V curves over 100 repetitive switching cycles when a surface roughness of 40 nm is employed. Further, for the CBA ReRAM, the current is the most stable when using the 40 nm-thick RS Si wafer at the high-resistance state and low-resistance state for 300,000 s in the retention test. These results show that use of the roughness substrate in the CBA ReRAM structure is effective in reducing variations in operating voltage and current.