GeSeTe for Enhanced Thermal Stability and Reliability in Ovonic Threshold Switching Materials.

Area of Science:

• Materials Science
• Electrical Engineering
• Solid-State Physics

Background:

• Ovonic Threshold Switching (OTS) selectors are crucial for high-density memory, but face thermal stability and reliability issues.
• Existing OTS selectors struggle with performance degradation under demanding conditions.

Purpose of the Study:

• To investigate the impact of germanium (Ge) content modulation on GeSeTe-based OTS selectors.
• To enhance the thermal stability and operational reliability of OTS selectors for memory applications.

Main Methods:

• Systematic study of GeSeTe compositions with varying Ge content.
• Fabrication and characterization of OTS selectors and selector-only memory (SOM) cells.
• High-temperature annealing (400 °C) and electrical testing (leakage current, switching speed, endurance).

Main Results:

• GeSeTe-based OTS selectors exhibited ultralow leakage current (~10^-9 A), nanosecond switching (~10 ns), and >10⁸ cycle endurance, even after 400 °C annealing.
• Optimized Ge content reinforced the covalent bonding network, improving performance.
• Excessive Ge content increased structural rigidity and introduced metastable defects, impacting performance.

Conclusions:

• Ge content engineering is vital for designing high-performance, thermally robust OTS selectors.
• GeSeTe-based SOM cells demonstrated stable switching with a 0.9 V memory window.
• Electric-field-driven atomic segregation mechanism elucidated polarity-dependent switching behavior.