Confining Cation Injection to Enhance CBRAM Performance by Nanopore Graphene Layer

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Conductive-bridge random access memory (CBRAM) utilizes resistive switching (RS) for nonvolatile data storage.
• RS behavior depends on conductive filament (CF) formation/dissolution driven by cation injection.
• Current methods suffer from non-localized cation injection, impacting device uniformity and reliability.

Purpose of the Study:

• To develop a method for localizing cation injection in CBRAM devices.
• To enhance the uniformity, endurance, and retention of CBRAM by controlling CF formation.
• To explore the potential of nano-scale ion barriers for high-performance memory.

Main Methods:

• Insertion of a monolayer graphene with nano-scale holes as an ion barrier between the active electrode and the resistive switching layer.
• Utilizing conductive atomic force microscopy (CAFM) to directly observe and confirm the localized conductive filament formation.
• Fabrication and characterization of a novel Cu/nanohole-graphene/HfO2/Pt CBRAM device.

Main Results:

• Direct CAFM evidence confirmed that conductive filament formation is confined to the nanohole of the graphene layer.
• The novel device demonstrated improved uniformity, endurance, and retention characteristics compared to standard CBRAM devices.
• The localized cation injection effectively limited ion migration, preventing excessive CF formation.

Conclusions:

• Nanohole graphene serves as an effective ion barrier to localize cation injection in CBRAM.
• This approach significantly enhances the performance and reliability of resistive switching memory devices.
• Further scaling of nanohole size offers a pathway towards atomic-scale control for single-CF-based CBRAM with superior performance.