Advancements in storage density and energy efficiency over the last decades have led to the miniaturization of magnetic memories, where state-of-the art bit sizes today lie deep in the sub-100 nm scale. However, probing the magnetic homogeneity of these bits is extremely challenging as it requires sufficient sensitivity and spatial resolution.
In a collaboration with imec, the Qnami Applab team approached this question by characterizing state-of-the art Spin-Transfer Torque Magnetoresistive Random-Access Memory (STT-MRAM) devices with ProteusQ. In the Qnami/imec work, the stray field of individual, encapsulated MRAM bits was measured. With this information, we characterized the switching statistics of 400 bits by using the MagnetoPQ. This allowed to link the switching behavior to the observed magnetic roughness of the devices. The characterization was done on encapsulated devices, sans electrical connectivity, situating our approach early in the process line – a stage where alternative nanoscale metology tools are currently absent. As a leading next-generation memory technology that is already in production, STT-MRAM perfectly exemplifies the impact of magnetic roughness measurements for emerging nanoelectronic technologies.
The work by the application team at Qnami together with imec has been recently published: A quantum sensing metrology for magnetic memories | npj Spintronics (nature.com), npj Spintronics volume 2, Article number: 14 (2024),
