Volatile threshold switching and synaptic properties controlled by Ag diffusion using Schottky defects

Area of Science:

• Materials Science
• Solid-State Electronics
• Neuroscience

Background:

• Memristors are crucial for next-generation computing, particularly for neuromorphic applications.
• Controlling ion diffusion in metal oxide structures is key to developing efficient memristive devices.

Purpose of the Study:

• To investigate a novel diffusion memristor structure (Ag/Ta2O5/HfO2/Pt) for mimicking biological brain functions.
• To analyze the device's performance, including power consumption, switching reliability, and synaptic properties.

Main Methods:

• Fabrication of a diffusion memristor with Ag/Ta2O5/HfO2/Pt structure.
• Characterization of device performance using electrical measurements (SET voltage, compliance current, cycle testing).
• Analysis of Ag ion diffusion using X-ray Photoelectron Spectroscopy (XPS) and Energy-Dispersive X-ray Spectroscopy (EDX).

Main Results:

• Achieved low power consumption (2 mW at 0.2 V SET voltage) and high selectivity (109).
• Demonstrated reliable and repeatable threshold switching over 20 cycles with minimal SET variation (SD=0.028).
• Verified volatile switching with biological synaptic properties (quantum conductance, short-term/long-term memory) due to controlled Ag ion diffusion.

Conclusions:

• The developed diffusion memristor exhibits promising low-power and neuromorphic capabilities.
• Controlled Ag ion diffusion in designed control and switching layers enhances device performance.
• Potential applications include selectors, synapses, and advanced neuromorphic computing devices.