Fig. 1: Structural comparison and thermal analysis of conventional and nano-confined phase change memory (PCM) cells.
From: Extended switching endurance of phase change memory through nano-confined cell structure
a–d Schematic illustration of the PCM cells, where the phase change layer (PCL) is sandwiched between the top TiN electrode and bottom heater, with each PCM cell connected to a controll circuit for individual device access through bottom electrode contact (BEC). a, c Conventional PCM cell structure with a flat TiN heater in direct contact with the PCL. b, d Nano-confined PCM cell structure, where the top of the TiN heater is embedded in the PCL, shifting the active switching region into the interior of the phase change material. e Cross-sectional transmission electron microscopy image of PCM devices subjected to cyclic tests. f Magnified cross-sectional bright-field scanning transmission electron microscopy image of a single PCM cell where the active switching region is outlined by dash curve locates above the lower boundary of PCL. g Finite element simulation of temperature distribution along the z-direction of PCM cell (from the bottom heater to top TiN electrode) after applying the RESET programming pulse. h, i Temperature distribution simulations of conventional and nano-confined PCM cells, respectively, which demonstrate that the nano-confined structure enhances heating efficiency within the PCL by ~50%, leading to reduced RESET current and improved endurance.
