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arXiv · 2604.14680

Anomalous Platinum and Oxygen Transport during Electroforming of NbOx Memristors

Shimul Kanti Nath·Sanjoy Kumar Nandi·Xiao Sun·Sujan Kumar Das·Bin Gong·Nicholas J. Ekins-Daukes·Deepak Mishra·Mahesh P. Suryawanshi·William D. A. Rickard·Songyan Yin·Michael P. Nielsen·Robert G. Elliman
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Abstract

Electroforming of metal-oxide-metal memristors is generally attributed to the creation of oxygen-vacancy filaments within the oxide, with noble metal electrodes such as Pt and Au remaining chemically inert. Here, we demonstrate that electroforming and subsequent operation of Pt/NbOx/Nb2O5/Pt devices can induce an unexpected and highly correlated redistribution of both oxygen and platinum. Time-of-flight secondary ion mass spectrometry reveals a filamentary pathway characterized by micrometer-scale oxygen enrichment extending from the Nb2O5 layer through NbOx and deep into the Pt top electrode. Surprisingly, this is accompanied by the formation of a Pt-rich filament penetrating the oxide stack along the same filamentary path. Finite-element and lumped-element modelling show that current-controlled negative-differential-resistance operation produces localized Joule heating and high-frequency thermal cycling, which strongly enhances oxygen migration and enables thermally assisted Pt diffusion along vacancy-rich pathways. These findings reveal a previously unrecognized metal-ion transport mechanism in NbOx memristors and highlight the critical role of post-forming electrical dynamics in determining filament chemistry, stability, and device reliability.

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Shimul Kanti Nath, Sanjoy Kumar Nandi, Xiao Sun, Sujan Kumar Das, Bin Gong, Nicholas J. Ekins-Daukes, Deepak Mishra, Mahesh P. Suryawanshi, William D. A. Rickard, Songyan Yin, Michael P. Nielsen, Robert G. Elliman. 2026-04-16. Anomalous Platinum and Oxygen Transport during Electroforming of NbOx Memristors. https://arxiv.org/abs/2604.14680

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