Nonvolatile memory devices with NiSi2/CoSi2 nanocrystals

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Development of non-volatile memory technologies is crucial for modern electronics.
• Metal silicide nanocrystals offer potential for high-density memory applications.
• Challenges remain in achieving stable and efficient memory characteristics.

Purpose of the Study:

• To fabricate and characterize metal-oxide-semiconductor (MOS) memory devices incorporating NiSi2 and CoSi2 nanocrystals.
• To investigate the memory properties, including hysteresis and retention, of these novel structures.
• To assess the compatibility of the fabrication process with existing semiconductor manufacturing.

Main Methods:

• Fabrication of MOS structures with NiSi2 and CoSi2 nanocrystals embedded in a silicon dioxide (SiO2) layer.
• Electrical characterization using capacitance-voltage (C-V) measurements to observe hysteresis.
• Evaluation of data retention characteristics.
• Integration of a hafnium dioxide (HfO2) layer as a control oxide.

Main Results:

• A pronounced capacitance-voltage hysteresis was observed, indicating memory functionality.
• A significant memory window of approximately 1 V was achieved under low programming voltages.
• The use of a HfO2 control oxide layer demonstrably improved the retention characteristics.
• The fabrication process was confirmed to be compatible with current semiconductor industry manufacturing standards.

Conclusions:

• NiSi2 and CoSi2 nanocrystals are effective charge storage elements in MOS memory devices.
• The developed memory structures exhibit promising performance for non-volatile memory applications.
• The integration of HfO2 enhances device reliability, paving the way for practical implementation.