Thermal Reliability Issues in ReRAM Memory Arrays

Abstract

A localized buildup of Joules heat occurs in a memory cell as a result of the switching of resistive memory (resistive random access memory, (ReRAM)) cells. In ReRAM memory crossbar architecture, heat accumulated in one cell transfers to nearby cells via shared electrode metal lines and impacts adversely the performance of the devices. The cell-to-cell heat transfer leads to reduced number of switching cycles (SWC) and, in specific circumstances, to a loss of a bit in the cell brought about by a rupturing of the nanofilament. This chapter identifies the main causes for the thermal ReRAM reliability issues, offers a detailed analysis of the intercell heat transfer, characterizes its effects on the electric behavior of cells, and describes the thermal cross-talk in terms of three key material properties: specific heat capacity, the mass given by the geometry of the conductor material, and thermal conductivity of the electrode. By depositing several distinct composite inert electrodes, multiple ReRAM arrays have been manufactured to alter deliberately the thermal conductivity, specific heat capacity, and the electrode geometry. The proposed thermal analysis, based on those electrode properties, accurately anticipates the experimentally discovered variations in the degradation of electric output characteristics of the ReRAM devices operated under the same conditions.