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

Abstract

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.

Multi-Level Control of Resistive RAM (RRAM) Using a Write Termination to Achieve 4 Bits/Cell in High Resistance State

“…However, in the absence of an access device, a large amount of leakage current (known as sneak-path current) flowing through unselected cells is inevitable, leading to the limitation of crossbar array sizes [6]. Regarding 3D, although eight-layer crossbar RRAM prototypes have been demonstrated, many of the manufacture-related issues including layer-dependent resistance variability are still not resolved [7]. Compared with the two abovementioned methods, MLC with its capability of storing more than a single bit of information in a single cell, is considered as one of the most promising properties of RRAM as it can increase the memory density without much change to current technologies.…”

A large memory window and low power consumption self‐rectifying memristor for electronic synapse

“…Introduction: Due to the simple structure, multi-level operation and non-volatile memory capacity, memristor has been considered a potential synapse device for constructing brain-inspired computing systems, which is expected to break the von Neumann bottleneck in the traditional computing system [1,2]. Nonetheless, the sneak current, flowing through unselected cells in passive crossbar array, will lead to read-out errors and failure of program operations.…”

A large memory window and low power consumption self-rectifying memristor for electronic synapse

“…Introduction: Due to the simple structure, multi-level operation and non-volatile memory capacity, memristor has been considered as a potential synapse device for constructing brain-inspired computing systems, which is expected to break the von Neumann bottleneck in traditional computing system [1,2]. Nonetheless, the sneak current, flowing through unselected cells in passive crossbar array, will lead to read-out errors and failure of program operations.…”