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Published on: May 13, 2020
Improving HfO2-Based Resistive Switching Devices by Inserting a TaO Thin Film via Engineered In Situ Oxidation.
Tao Wang1, Stefano Brivio2, Elena Cianci2
1Institute of Functional Nano & Soft Materials, Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, 199 Ren-Ai Road, Suzhou 215123, China.
New resistive switching (RS) devices using a tantalum oxide/hafnium oxide (TaO/HfO2) bilayer show improved performance for artificial neural networks. This novel fabrication method enhances yield, reliability, and synaptic plasticity, overcoming limitations of current HfO2-based devices.
Area of Science:
- Materials Science
- Electrical Engineering
- Nanotechnology
Background:
- Resistive switching (RS) devices are crucial for artificial neural networks (ANNs) due to their binary and analog capabilities.
- Current RS devices based on hafnium dioxide (HfO2) have performance limitations, including variability and low yield, hindering industrial adoption.
- Improving the performance and reliability of RS devices is essential for advancing neuromorphic computing hardware.
Purpose of the Study:
- To fabricate and characterize novel resistive switching devices using a tantalum oxide/hafnium dioxide (TaOx/HfO2) bilayer stack.
- To investigate a new in situ fabrication method for creating the TaOx layer within an atomic layer deposition (ALD) process.
- To compare the performance of the bilayer RS devices against traditional single-layer HfO2 devices.
Main Methods:
- Fabrication of TaOx/HfO2 bilayer stacks using in situ oxidation of a tantalum film during HfO2 deposition via atomic layer deposition (ALD).
- Structural characterization using X-ray reflectivity (XRR) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) to analyze film structure and composition.
- Comprehensive electrical characterization to evaluate switching performance, variability, reliability, and synaptic plasticity.
Main Results:
- The TaOx film exhibited a substoichiometric structure, and the TaOx/HfO2 bilayer demonstrated a well-layered structure.
- TaOx/HfO2-based RS devices showed significantly improved switching performance compared to single-layer HfO2 devices.
- Key advantages include higher forming yield, self-compliant switching, reduced switching variability, enhanced reliability, and superior synaptic plasticity.
Conclusions:
- The novel in situ fabrication of TaOx/HfO2 bilayer stacks offers a promising pathway for developing high-performance resistive switching devices.
- These improved RS devices address critical limitations in variability and yield, making them suitable for industrial applications in artificial neural networks.
- The enhanced electrical properties pave the way for more efficient and reliable neuromorphic computing hardware.
