R&D: Multi-physics Modeling of Phase Change Memory Operations in Ge-rich Ge2 Sb2 Te5 Alloys

Journal of Applied Physics has published, in special collection Phase-change Materials and Their Applications, an article written by Robin Miquel, STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles, France, Université Grenoble Alpes, CEA, Leti, F-38000 Grenoble, France, and Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau, France, Thomas Cabout, STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles, France, Olga Cueto, Université Grenoble Alpes, CEA, Leti, F-38000 Grenoble, France, Benoit Sklénard, Université Grenoble Alpes, CEA, Leti, F-38000 Grenoble, France, and Mathis Plapp, Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau, France.

Abstract: “One of the most widely used active materials for phase-change memories (PCM), the ternary stoichiometric compound Ge 2 Sb 2 Te 5 (GST), has a low crystallization temperature of around 150 ° C⁠. One solution to achieve higher operating temperatures is to enrich GST with additional germanium. This alloy crystallizes into a polycrystalline mixture of two phases, GST and almost pure germanium. In a previous work [R. Bayle et al., J. Appl. Phys. 128, 185 101 (2020)], this crystallization process was studied using a multi-phase field model (MPFM) with a simplified thermal field calculated by a separate solver. Here, we combine the MPFM and a phase-aware electrothermal solver to achieve a consistent multi-physics model for device operations in PCM. Simulations of memory operations are performed to demonstrate its ability to reproduce experimental observations and the most important calibration curves that are used to assess the performance of a PCM cell.“