Optimization of Bilayer Resistive Random Access Memory Based on Ti/HfO₂/ZrO₂/Pt

Area of Science:

• Materials Science
• Electrical Engineering
• Solid-State Physics

Background:

• Resistive random-access memory (RRAM) devices offer promising non-volatile memory solutions.
• Understanding the electrothermal coupling and filament formation is crucial for RRAM optimization.
• Metal oxide RRAM structures, like Ti/HfO2/ZrO2/Pt, require detailed modeling for performance enhancement.

Purpose of the Study:

• To develop and validate an electrothermal coupling model for a Ti/HfO2/ZrO2/Pt bilayer RRAM structure.
• To investigate the impact of conductive filament dimensions and dielectric layer thicknesses on RRAM performance.
• To identify optimal device geometry and top electrode material for enhanced resistance switching characteristics.

Main Methods:

• Utilized COMSOL Multiphysics software to simulate a 2D axisymmetrical RRAM structure.
• Analyzed the SET and RESET switching mechanisms within the Ti/HfO2/ZrO2/Pt device.
• Systematically varied conductive filament (CF1, CF2) widths/thicknesses and dielectric ratios to assess electrical performance.

Main Results:

• Device performance is significantly influenced by conductive filament dimensions and dielectric layer thicknesses.
• Optimal width and thickness ratios (conductive filament to transition layer 6:14, HfO2 to ZrO2 7.5:7.5) result in stable high and low resistance states.
• The Ti top electrode material exhibited the highest resistance switching ratio (~11.67) compared to Pt and Al.

Conclusions:

• A validated electrothermal coupling model for Ti/HfO2/ZrO2/Pt RRAM was established.
• Optimal geometric parameters and the Ti electrode material were identified for stable and high-performance RRAM operation.
• The study provides insights into the resistance mechanism and optimal design for RRAM hysteresis characteristics, achieving a switching ratio of 10.46.