Direct visualization and 3D reconstruction of conductive filaments in aSiO₂ material-based memristive device

Area of Science:

• Materials Science
• Solid-State Physics
• Nanotechnology

Background:

• Conductive filaments are crucial for understanding memristive device operation.
• Previous theoretical models lacked direct visualization of filament morphology.

Purpose of the Study:

• To visualize and reconstruct conductive filaments in a Cu/Cu-doped SiO2/W memristive device.
• To investigate the role of Joule heating in filament evolution and defect formation.
• To develop a methodology for 3D reconstruction of filaments for failure analysis.

Main Methods:

• Focused Ion Beam (FIB) milling in top-down and front-back modes.
• Scanning Electron Microscopy (SEM) imaging of the device after DC sweep cycles.
• 3D reconstruction of conductive filaments and defects from FIB-SEM images.

Main Results:

• Joule heat significantly influences conductive filament morphology, causing vaporization and creating defects like particles, voids, and cavities.
• The interplay between filament formation and vaporization leads to substantial current fluctuations.
• Exfoliation of adjacent single layers by vaporized material was observed.

Conclusions:

• The study provides a detailed 3D visualization of conductive filaments and associated defects in memristive devices.
• Joule heating is identified as a key factor in memristor degradation and current instability.
• The developed FIB-based methodology offers a promising approach for future memristive device failure analysis.