Layer-dependent resistance variability assessment on 2048 8-layer 3D vertical RRAMs.

Non-filament 3D vertical RRAM (VRRAM) is a promising technology for emerging high-density memory applications. In this Letter, the layer-dependent resistance variability at both low resistance state (LRS) and high resistance state (HRS) is assessed on state-of-the-art 8-layer 3D VRRAMs. 2048 devices are measured with the aid of an FPGA-controlled relay matrix which enables automated switching of devices without changing the cabling. The results show LRS exhibits little layer dependence while both the average and the standard variation of HRS decrease from the top layer to the bottom layer. A qualitative speculation is proposed to explain the observation based on the high-resolution transmission electronic microscope image. This work is beneficial for future 3D VRRAM circuit design and performance improvement. [ABSTRACT FROM AUTHOR]