Controlling the Formation of Conductive Pathways in Memristive Devices. Issue 33 (8th September 2022)

• Record Type: Journal Article
• Authors: Winkler, Robert; Zintler, Alexander; Petzold, Stefan; Piros, Eszter; Kaiser, Nico; Vogel, Tobias; Nasiou, Déspina; McKenna, Keith P.; Molina‐Luna, Leopoldo; Alff, Lambert
• Is Part Of: Advanced science. Volume 9:Issue 33(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-08
• Subjects: first principle calculation -- grain boundary atomic structures -- hafnium oxide -- resistive switching memory -- scanning transmission electron microscopy; Science -- Periodicals; 505
• DOI: 10.1002/advs.202201806
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: Resistive random‐access memories are promising candidates for novel computer architectures such as in‐memory computing, multilevel data storage, and neuromorphics. Their working principle is based on electrically stimulated materials changes that allow access to two (digital), multiple (multilevel), or quasi‐continuous (analog) resistive states. However, the stochastic nature of forming and switching the conductive pathway involves complex atomistic defect configurations resulting in considerable variability. This paper reveals that the intricate interplay of 0D and 2D defects can be engineered to achieve reproducible and controlled low‐voltage formation of conducting filaments. The author find that the orientation of grain boundaries in polycrystalline HfO x is directly related to the required forming voltage of the conducting filaments, unravelling a neglected origin of variability. Based on the realistic atomic structure of grain boundaries obtained from ultra‐high resolution imaging combined with first‐principles calculations including local strain, this paper shows how oxygen vacancy segregation energies and the associated electronic states in the vicinity of the Fermi level govern the formation of conductive pathways in memristive devices. These findings are applicable to non‐amorphous valence change filamentary type memristive device. The results demonstrate that a fundamental atomistic understanding of defect chemistry is pivotal to design memristors as key element of future electronics. Abstract : By combining ultra‐high‐resolution experimental and theoretical methods, a direct correlation between the grain boundary atomic and electronic structures with the electroforming behavior of TiN/ m ‐HfO2 /Pt memristors with defined HfO2 textures is established. The paper reveals how the interaction of different defect types governs the formation of conductive pathways in memristors based on filamentary switching in oxides.