SYNAPSE

The SYNAPSE project aimed at the metalorganic chemical vapor phase deposition (MOCVD) and study of chalcogenide single material, (core) and double material (core-shell) nanowires (NWs), for innovative multi-level phase change memories (PCM) based on  (In)Ge-Sb-Te alloys. At the same time, a great attention is currently devoted to the chance to downscale PCM cells by employing chalcogenide NWs. Different material combinations (Ge-Sb-Te/In-Sb-Te/In-GeTe) had to be explored in the realization of the CS-NWs, in order to expand the memory level operational features of the obtainable PCM devices. Moreover, NWs of different chalcogenide alloys, including Ge-based and In-based telluride, were explored for their application to PCM devices both as single nanocells and in ordered arrays, this representing an important contribution to the achievement of downsized and low-power consumption non-volatile memory cells. A detailed study of the NW phase switching behavior (reversible amorphous-crystalline transitions) was carried out and correlated, as well as  the investigation of electrical and thermal properties of the NWs, their phase formation/crystallization dynamics, size-dependent effects and structural/chemical composition. Experimental work is supported by theoretical modeling and simulation of both crystallization dynamics and electro-thermal behavior.

Project partners

• CNR Italia: IMM Agrate (Coordinatore M.Longo),  IMEM Parma (L Lazzarini, L Nasi, V Grillo)
• University of Milano Bicocca (Milano, Italy)
• Micron Semiconductors Italia S.r.l.
• Air Liquide (Francia)
• Institut de Mécanique et d'Ingénierie de Bordeaux Department TREFLE (Francia)
• FZJ - Peter Grünberg Institute, Division Semiconductor Nanoelectronics (Julich, Germania)
• Tyndall National Institute (Cork, Ireland)

Related publications

• "Crystal structure assessment of Ge–Sb–Te phase change nanowires",  E Rotunno, L Lazzarini, M Longo, and V Grillo, Nanoscale 5 (4), 1557-1563 (2013) https://pubs.rsc.org/en/content/articlelanding/2013/nr/c2nr32907g
• "Au-catalyzed synthesis and characterisation of phase change Ge-doped Sb–Te nanowires by MOCVD", M Longo, T Stoycheva, R Fallica, C Wiemer, L Lazzarini, and E Rotunno, Journal of crystal growth 370, 323-327 (2013) https://www.sciencedirect.com/science/article/pii/S0022024812006562
• "A Novel Sb₂Te₃ Polymorph Stable at the Nanoscale", E Rotunno, M Longo, C Wiemer, R Fallica, D Campi, M Bernasconi, AR Lupini, SJ Pennycook, and L Lazzarini, Chemistry of Materials 27 (12), 4368-4373 (2015) https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.5b00982
• "MOCVD growth and structural characterization of In–Sb–Te nanowires", S Selmo, S Cecchi, R Cecchini, C Wiemer, M Fanciulli, E Rotunno, L Lazzarini, and M Longo, Physica status solidi (a) 213 (2), 335-338 (2016) https://onlinelibrary.wiley.com/doi/abs/10.1002/pssa.201532381
• "Low power phase change memory switching of ultra-thin In₃Sb₁Te₂ nanowires", S Selmo, R Cecchini, S Cecchi, C Wiemer, M Fanciulli, E Rotunno, L Lazzarini, M Rigato, D Pogany, A Lugstein, and M Longo, Applied Physics Letters 109 (21), 213103 (2016) https://aip.scitation.org/doi/10.1063/1.4968510