A quantum sensing metrology for magnetic memories

Area of Science:

• Materials Science
• Quantum Technology
• Semiconductor Physics

Background:

• Magnetic random-access memory (MRAM) is a key emerging non-volatile memory technology.
• Controlling device property distributions is crucial for MRAM advancement and new applications.
• Current metrology methods often rely on ensemble averaging, limiting individual bit analysis.

Purpose of the Study:

• To introduce a non-contact metrology technique for individual MRAM bit characterization.
• To investigate MRAM performance at the nanoscale using scanning NV magnetometry (SNVM).
• To assess bit-to-bit uniformity and identify underperforming bits.

Main Methods:

• Utilized scanning NV magnetometry (SNVM) for non-contact characterization.
• Performed magnetic reversal characterization on individual MRAM bits (<60 nm).
• Benchmarked two distinct bit etching processes post-pattern formation.

Main Results:

• Successfully extracted magnetic properties, thermal stability, and switching statistics from individual MRAM bits.
• Demonstrated the ability to gauge bit-to-bit uniformity.
• Identified 'tail-bits' at array edges, enabling targeted failure analysis, unlike ensemble methods.

Conclusions:

• SNVM is a powerful tool for nanoscale quantum sensing of MRAM devices.
• This technique facilitates early-stage screening in semiconductor manufacturing lines.
• Potential for integrating SNVM as a standard nanoscale characterization tool in the industry.