A quantum sensing metrology for magnetic memories

TL;DR

This paper presents a non-contact quantum sensing technique using Scanning NV Magnetometry to analyze magnetic properties and uniformity of nanoscale MRAM bits, enabling improved device characterization and process optimization.

Contribution

It introduces a novel nanoscale quantum sensing method for detailed magnetic characterization of individual MRAM bits, revealing process-dependent switching behaviors.

Findings

Demonstrated magnetic reversal characterization in <60 nm bits

Identified process-induced differences in switching behavior

Showcased potential for early-stage screening in manufacturing

Abstract

Magnetic random access memory (MRAM) is a leading emergent memory technology that is poised to replace current non-volatile memory technologies such as eFlash. However, the scaling of MRAM technologies is heavily affected by device-to-device variability rooted in the stochastic nature of the MRAM writing process into nanoscale magnetic layers. Here, we introduce a non-contact metrology technique deploying Scanning NV Magnetometry (SNVM) to investigate MRAM performance at the individual bit level. We demonstrate magnetic reversal characterization in individual, < 60 nm sized bits, to extract key magnetic properties, thermal stability, and switching statistics, and thereby gauge bit-to-bit uniformity. We showcase the performance of our method by benchmarking two distinct bit etching processes immediately after pattern formation. Unlike previous methods, our approach unveils marked differences in switching behaviour of fully contacted MRAM devices stemming from these processes. Our findings highlight the potential of nanoscale quantum sensing of MRAM devices for early-stage screening in the processing line, paving the way for future incorporation of this nanoscale characterization tool in the semiconductor industry.