Coordinated sub-cycle modulation atomic layer deposition of atomically homogeneous GeTe₉ thin films for...

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• High-density 3D memory architectures face challenges with leakage current suppression.
• Ovonic threshold switches (OTS) are crucial for 3D phase-change memory (PCM).
• Te-rich chalcogenides offer low threshold voltage and fast switching for OTS, but are difficult to deposit uniformly via conventional Atomic Layer Deposition (ALD).

Purpose of the Study:

• To develop a novel deposition method for uniform, high-Te-content materials for OTS applications.
• To overcome the limitations of conventional ALD in achieving atomic intermixing in extreme-ratio materials.
• To demonstrate improved performance in OTS devices fabricated using the new method.

Main Methods:

• Introduction of a coordinated sub-cycle modulation (CSM) strategy.
• Synchronization of GeTe/Te sub-cycle ratio with interfacial diffusion kinetics.
• Fabrication and characterization of OTS devices using ALD-deposited GeTe9 films.

Main Results:

• Achieved ALD of GeTe9 films with atomic-level homogeneity and amorphous structure.
• Fabricated OTS devices exhibit high off-state resistance (10^7 Ω).
• Demonstrated ultra-fast switching speed (4 ns) and excellent cycle endurance (>10^9 cycles).

Conclusions:

• CSM strategy enables the synthesis of extreme-ratio, non-stoichiometric functional materials via ALD.
• The developed Te-rich OTS materials provide a viable selector solution for 3D memory.
• This work establishes CSM as a generalizable paradigm for advanced materials synthesis.