R&D: Innovative Nanocomposites for Low Power PCM: GeTe/C Multilayers

Physica Status Solidi, Rapid Research Letters has published an article written by Damien Térébénec, Nicolas Bernier, Niccolo Castellani, Mathieu Bernard, Université Grenoble Alpes, CEA, Leti, F-38000 Grenoble, France, Jean-Baptiste Jager, Université Grenoble Alpes, CEA, IRIG, F-38000 Grenoble, France, Martina Tomelleri, Jessy Paterson, Marie-Claire Cyrille, Nguyet-Phuong Tran, Université Grenoble Alpes, CEA, Leti, F-38000 Grenoble, France, Valentina M. Giordano, ILM, UMR 5306 University Lyon 1-CNRS, F-69622 Villeurbanne Cedex, France, Françoise Hippert, Université Grenobles Alpes, CNRS, Grenoble INP, LMGP, F-38000 Grenoble, France, and Pierre Noé, Université Grenoble Alpes, CEA, Leti, F-38000 Grenoble, France.

Abstract: “Innovative nanocomposites consisting of [(GeTe)_4 nm/C_1 nm]₁₀ multilayers (MLs) deposited by magnetron sputtering are integrated in phase-change memory (PCM) test devices with a ‘wall structure.’ Scanning transmission electron microscopy (STEM) shows that an ML structure, with crystallized GeTe layers, is kept after integration in as-fabricated devices and also after an additional annealing of the devices at 425 °C. The programming current (RESET current) required to reach the high resistance state of [(GeTe)_4 nm/C_1 nm]₁₀ ML devices decreases by 45% after annealing at 425 °C. The reduction in RESET current is 55% and the reduction in drift coefficient is about 40% in ML devices annealed at 425 °C compared to similar devices incorporating Ge₂Sb₂Te₅. STEM imaging, coupled with nano-beam electron diffraction and electron energy loss spectroscopy, of ML devices in the high resistance state shows that the RESET current reduction after annealing is correlated to a reduction of the amorphized volume.“