Analysis of the Electrical ReRAM Device Degradation Induced by Thermal Cross-Talk

A switching of resistive memory cells leads to a local accumulation of Joules heat in the device. In resistive RAM (ReRAM) arrays, the heat generated in one cell spreads via common electrode metal lines to the neighboring cells and may cause their performance degradation. The performance degradation results in reduced number of switching cycles and, in extreme cases, even in a loss of a bit, caused by the rupture of the nanofilament. The authors propose a thermal analysis of the thermal cross-talk, describe its impact on cells' electric performance, and identify three major mechanisms for the ReRAM reliability: (i) thermal conductivity, (ii) the specific heat capacity, and (iii) geometry of the electrodes. Several ReRAM arrays are manufactured to vary thermal conductivity, specific heat and geometry of the electrodes by depositing eight different inert electrodes: Pt(50 nm)/Ti(30 nm), Ru(50 nm)/Ti(30 nm), Co(50 nm)/Ti(30 nm), Pt(50 nm/Cu(100 nm)/Ti(30 nm), Pt(50 nm)/ Cu(200 nm)/Ti(30 nm), Ru(50 nm/Cr(30 nm), Ru(50 nm)/Ti(50 nm), and Rh(50 nm)/Cr(30 nm). The experimentally found differences of the degradation of electric performance of the array cells performed under identical circumstances can be correctly predicted by the proposed thermal analysis using the material properties and geometry parameters of the electrodes.