PSA-STT-MRAM Solution for Extended Temperature Stability

Lequeux, S., Almeida, T. , Caçoilo, N., Palomino, A., Prejbeanu, I. L., Sousa, R. C., Cooper, D. and Dieny, B. (2021) PSA-STT-MRAM Solution for Extended Temperature Stability. In: 2021 IEEE International Memory Workshop (IMW), Dresden, Germany, 16-19 May 2021, ISBN 9781728185170 (doi: 10.1109/IMW51353.2021.9439609)

Abstract

The concept of Perpendicular Shape Anisotropy (PSA) spin transfer torque (STT) MRAM has been recently proposed as a solution to achieve downsize scalability of MRAM below sub-10 nm technology nodes, down to 3-4 nm cell size lateral dimensions. In conventional p-STT-MRAM, at sub-20 nm diameters, the perpendicular anisotropy arising from the MgO/CoFeB interface becomes too weak to ensure sufficient stability of the storage layer magnetization. In addition, this interfacial anisotropy decreases rapidly with increasing temperature, resulting in a significant drawback for applications having to operate on a wide temperature range. Here, we combine both coercivity and electron holography measurements as function of temperature to show that in a PSA storage layer, the source of anisotropy is much more robust versus temperature compared to the interfacial anisotropy of conventional STT-MRAM stacks. This allows to considerably reduce the temperature dependence of coercivity. This property is quite beneficial for applications having to operate on an extended temperature range, such as automotive (-40°C to 150°C), or to fulfill solder reflow compliance requiring 1 minute retention at 260°C.

• Item Type: Conference Proceedings
• Additional Information: This work was partly funded by the ERC advanced grant MAGICAL n°669204, the ERC Starting grant Holoview Nº306535 and the Carnot project MAGICMAPS.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Almeida, Dr Trevor
• Authors: Lequeux, S., Almeida, T., Caçoilo, N., Palomino, A., Prejbeanu, I. L., Sousa, R. C., Cooper, D., and Dieny, B.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• ISSN: 2573-7503
• ISBN: 9781728185170
• Copyright Holders: Copyright © 2021 IEEE
• First Published: First published in Proceedings of the 2021 IEEE International Memory Workshop (IMW)
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher