Affiliation:
1. Division of Electronics and Electrical Engineering Dongguk University Seoul 04620 Republic of Korea
2. Department of Electrical and Computer Engineering and Inter‐university Semiconductor Research Center (ISRC) Seoul National University Seoul 08826 Republic of Korea
3. School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA 30332 USA
4. School of Electrical and Computer Engineering University of Seoul Seoul 02504 Republic of Korea
Abstract
AbstractThis study implements a highly uniform 3D vertically stack resistive random‐access memory (VRRAM) with a four‐layer contact hole structure. The fabrication process of a four‐layer VRRAM is demonstrated, and its physical and electrical properties are thoroughly examined. X‐ray photoelectron spectroscopy and transmission electron microscopy are employed to analyze the chemical distribution and physical structure of the VRRAM device. Multilevel capability, reliable endurance (>104 cycles), and retention (104 s) are successfully obtained. Synaptic memory plasticity, such as spike time‐dependent plasticity, spike rate‐dependent plasticity, excitatory post‐synaptic current, paired‐pulse facilitation, and long‐term potentiation and depression is presented. Finally, the vector‐matrix multiplication (VMM) operation is conducted on a 4 × 12 VRRAM array, according to the low resistance state ratio. It is ascertained that the accuracy drop, which can occur due to VMM error, can be limited to a decrease of less than 0.44% point. Utilizing the high‐density, multilevel, and biological characteristics of VRRAM, it is possible to implement high‐performance neuromorphic systems that require densely integrated synaptic devices.
Funder
National Research Foundation of Korea
Subject
Electrochemistry,Condensed Matter Physics,Biomaterials,Electronic, Optical and Magnetic Materials