The parasitic effects induced by the contact in RRAM with MIM structure

This paper has reported a programmable switch composed of copper-doped-SiO₂ sandwiched between Cu top electrode and inert W bottom electrode. Reproducible rectifying-like I-V performance was found in the device with top electrode (TE), while with regard to the cell without TE, no rectifying-like I-V characterization was observed. This rectifying-like I-V curve is properly caused by electrode contact. To further prove the effect of TE, R_ON retention behavior of the device with TE and without TE were investigated. The testing results clearly showed that the R_ON retention property of device with TE was worse than that without TE. We propose a model for the interface between top electrode and copper-doped-SiO₂ to interpret this rectifying-like performance, which indicates that interface rectifying-like effect emerges when on-resistance is comparable with the resistance of diode-like junction between metal contact and resistive-material. The results suggest that optimizing interface condition or adjusting resistive material with large on-resistance is essential for robust MIM RRAM design.