Thermal and Signal Integrity Improvement in a 3D RRAM Crossbar with Carbon Nanotube Interconnects

The focus of this paper is to explore the implementation of resistive random-access memory (RRAM) cells in monolithic integration while addressing the reliability issues that can affect the efficiency of the memory. Specifically, the paper addresses the use of Nickel (Ni) interconnects as a conventional material and the high resistivity and temperatures resulting from Set/Reset switching. The paper proposes using carbon nanotubes (CNT) as an alternative material to improve signal and thermal integrity. The paper analyzes the electrothermal 1D1R structure and compares the conventional Ni metal electrodes to the CNT ones using a full 3D numerical model to provide electrical and thermal responses. The study enhances the accuracy of the model by considering the temperature-dependent electrical and thermal conductivity of the conductive filament and oxide. The paper also introduces a new structure called 1D1R-1R1D that allows for resistive switching for all layers and increases the density of the crossbar memory while addressing problems with the conventional structure. The paper analyzes the issues of voltage drop along wires and thermal crosstalk in both horizontal and vertical directions. The results of this study demonstrate the potential benefits of CNT interconnects for improving the thermal and signal integrity of RRAM crossbars.