| 초록 |
Phase change memory (PCM) is an emerging non-volatile technology that utilizes Ge2Sb2Te5 (GST), a chalcogenide material, whose conductive crystalline and resistive amorphous phases correspond to data 0 and 1, respectively. The switching mechanism includes phase-change phenomena such as melting, quenching, and annealing that are controlled by Joule heating. In this work, we present our simulation results on the falling-time controlled, i.e., cooling-speed controlled, switching operations. The falling-time varied from 10 to 100 ns. The molten GST freezes to become amorphous when cooled rapidly while it recrystallizes when cooled slowly. We constructed a switching model for PCM by combining electrothermal and phase-field models in a finite element analysis package, COMSOL Multiphysics. We analyzed the variability in resulting resistance that is caused by the stochastic nature of the nucleation. We conducted a comparative study on two cell architectures: one is heater-based and the other is self-heating. The device performance such as reset current, power consumption, on/off ratio, etc, along with cell resistance statistics were compared |
