Évènements

14 Dec
14/12/2020 14:00

Sciences & Société

Soutenance de thèse : Prabir MAHATO

Etude et développement de mémoires résisitives pour l’électronique flexible / Study and development of resistive memories for flexible electronic applications

Doctorant : Prabir MAHATO

Laboratoire INSA : INL

Ecole doctorale : ED160 : Électronique, Électrotechnique et Automatique

The advent of flexible electronics has brought about rapid research towards sensors, bio implantable and wearables devices for assessment of diseases such as epilepsy, Parkinson’s and heart attacks. Memory devices are major component in any electronic circuits, only secondary to transistors, therefore many research efforts are devoted to the development of flexible memory devices. Conductive Bridge Random Access Memories (CBRAMs) based on creation/dissolution of a metallic filament within a solid electrolyte are of great research interest because of their simple Metal Insulator Metal architecture, low-voltage capabilities, and compatibility with flexible substrates. In this work, instead of a conventional metallic oxide or a chalcogenide layer, a bio-compatible polymer - Polyethylene Oxide (PEO) – is employed as the solid electrolyte layer using water as solvent. Memory devices, consisting in Ag/PEO/Pt tri-layer stacks, were fabricated either on silicon and flexible substrates using an heterogeneous process combining Physical Vapour Deposition and spin coating. To this aim, a systematic study on the effect of solution concentration and deposition speed on the PEO thickness is presented. SEM/EDX and AFM measurements were then conducted on devoted “nano-gap” planar structures and have revealed the formation of metallic Ag precipitates together with morphological changes of the polymer layer after resistance switching. The performance of the resistive memory devices is then assessed on silicon and flexible substrate. In particular programming voltage statistics, OFF/ON resistance ratio, endurance cycles and retention tests are performed and the effect of current compliance is analysed. The conduction mechanism in the HRS/LRS is studied on the Ag/PEO/Pt and Pt/PEO/Pt reference devices. Finally, the electrical characterization of devices on flexible substrate is performed under mechanical stress, showing promising results. Polymer-based CBRAM devices are therefore suggested as potential candidates for sustainable development of flexible memory devices.