Nonvolatile floating-gate memories using Zr and ZrO2 nanodots

Area of Science:

• Materials Science
• Nanotechnology
• Electrical Engineering

Background:

• Nonvolatile memory devices are crucial for data storage.
• Developing robust and efficient memory structures is an ongoing challenge.
• Utilizing nanodots for charge trapping offers potential for improved memory performance.

Purpose of the Study:

• To fabricate and characterize novel triple-layer SiO2/Zr nanodots (NDs)/SiO2 structures for nonvolatile memory applications.
• To investigate the structural and electrical properties of these memory structures before and after annealing.
• To optimize the memory performance by controlling the amount of Zr nanodots.

Main Methods:

• Fabrication of SiO2/Zr NDs/SiO2 structures using ion beam sputtering deposition (IBSD) at room temperature.
• Characterization using high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS).
• Electrical property evaluation via capacitance-voltage (C-V) measurements to determine the memory window.

Main Results:

• Successfully fabricated triple-layer SiO2/Zr NDs/SiO2 structures at room temperature.
• Confirmed transformation of Zr NDs to ZrO2 NDs upon annealing via HRTEM and XPS.
• Observed a significant increase in memory window up to 5.8 V with increasing Zr amount (up to 6 monolayers) in annealed samples.
• Demonstrated improved memory performance (larger memory window, reduced charge-loss rate) after annealing due to double oxide barriers (SiO2 and ZrO2).

Conclusions:

• Room-temperature fabrication of SiO2/Zr/SiO2 nonvolatile memory structures is feasible using IBSD.
• Annealing is critical for transforming Zr to ZrO2, enhancing memory characteristics.
• The optimized triple-layer structure with ZrO2 nanodots shows promising potential for high-performance nonvolatile memory devices.