Chalcogenide nanocomposite materials with improved thermal properties for development of phase-change memories with low power consumption and high thermal stability

Published : 15 July 2019

Phase-change memories (PCM) are the best candidates in order to replace Flash memories, for the realization of universal SCM memory (Storage Class Memory) bridging the gap between volatile and non volatile memories as well as for neuromorphic and articificial intelligence. Nevertheless, PCM face a major limit related to programming currents that are too high for future memory generations. Thus, the control of thermal transport at the nanoscale to limit energy consumption is a key parameter in order to optimize the Joule effect at play during programming of the PMC memory cell. Nevertheless, the thermal management at nanoscale is still poorly understood. Thus, this thesis aims at developing new Ge-Sb-Te phase-change materials and new architectures for manufacturing PCM memories operating at lower power and improved thermal stability for Embedded applications.

These objectives can be achieved both by optimizing the Ge-Sb-Te phase-change material (nanostructuring, multilayer, composition) and thermal confinement of the memory cell.

The development (PVD deposits on industrial tool in clean rooms) and the characterization of these new nanostructured GST materials (XRD, resistivity and magneto-transport/Hall, FTIR/Raman/reflectivity, Synchrotron characterization, etc.) will be carried out at CEA-Leti. The characterization of the thermal transport (thermal conductivity Kth, RUS, Brillouin Scatt., US Laser, Inelastic Scatt., VDoS, …) and its modeling will be performed at the ILM (CNRS-Univ. C. Bernard-Lyon). PCM devices in order to assess the properties of the new materials developped in this thesis (performance, reliability) will be fabricated on the Si technological Platform of LETI as well as at our industrial partner STMicroelectronics at Crolles.

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