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%0 Thesis %A Stasner, Pascal %T Nanofabrication and device engineering solutions for improved resistive switching reliability %I Rheinisch-Westfälische Technische Hochschule Aachen %V Dissertation %C Aachen %M RWTH-2025-07435 %P 1 Online-Ressource : Illustrationen %D 2025 %Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University %Z Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2025 %X Resistive switching based on the filamentary valence change mechanism (VCM) enables the resistance modulation of a normally insulating oxide by a conductive oxygen-deficient filamentary region. Current research is using this ability of devices to set the resistance to two or more different states for novel non-volatile memory concepts such as redox-based random access memory (ReRAM) or computation-in-memory. Here, the conductivity of the device is controlled by applying electrical stimuli that cause a redistribution of oxygen vacancies in the nanoscaled filament. However, the stochastic nature of the filament formation and redistribution is the source of many reliability problems that prevent widespread industrial use of VCM devices. This dissertation addresses the challenges in resistance state write-variability, instability and analog resistance modulation with a focus on device development and nanofabrication. Optimization of filament stability requires control of the migration of oxygen vacancies in the switching oxide, which is not affected by conventional electrode scaling. Here, a new device concept is proposed in which the volume of the switching oxide, and thus the filament, is laterally confined to 10 nm. The practical device fabrication with sub-lithographic scaling is implemented in two steps: the oxide nano-fin and the oxide nano-pillar device. The resistive switching of the nanofin device with a lateral oxide dimension of 10 nm is demonstrated with over 100,000 switching cycles without any sign of failure. The reliability improvement due to filament confinement is quantified for the nano-devices using electrical measurements compared to unscaled reference cells. The results show a reduction in write-variability and instability of the high-resistance state, which is particularly sensitive to oxygen vacancy migration. Further investigations promise a further improvement in reliability through full lateral filament confinement in the oxide nano-pillar device concept. The feasibility of process integration is demonstrated on a successfully resistive switching device. In order to present meaningful behavioral trends of various device engineering approaches, despite the variability-prone nature of VCM, a measurement methodology is being developed that rapidly captures data sets of over 1,000,000 switching cycles with 2,500 individually parameterized control parameters. This allows the identification of device characteristics that stabilize well-controlled analog SET processes independent of operation parameters. The experimental implementation of the concept proposed in this work motivates a focus shift of future research from the prevalent electrode scaling to filament confinement by scaling the switching oxide volume. This will improve the reliability of VCM devices, especially in combination with other device engineering approaches investigated here. %F PUB:(DE-HGF)11 %9 Dissertation / PhD Thesis %R 10.18154/RWTH-2025-07435 %U https://publications.rwth-aachen.de/record/1017604