  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.
