Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices
Perpendicular shape anisotropy (PSA) and double magnetic tunnel junctions (DMTJs) offer practical solutions to downscale spin-transfer-torque Magnetic Random-Access Memory (STT-MRAM) beyond 20 nm technology nodes, while retaining their thermal stability and reducing critical currents applied. Howeve...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
AIP Publishing LLC
2022-06-01
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| Series: | APL Materials |
| Online Access: | http://dx.doi.org/10.1063/5.0096761 |
| _version_ | 1818536337995726848 |
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| author | Trevor P. Almeida Alvaro Palomino Steven Lequeux Victor Boureau Olivier Fruchart Ioan Lucian Prejbeanu Bernard Dieny David Cooper |
| author_facet | Trevor P. Almeida Alvaro Palomino Steven Lequeux Victor Boureau Olivier Fruchart Ioan Lucian Prejbeanu Bernard Dieny David Cooper |
| author_sort | Trevor P. Almeida |
| collection | DOAJ |
| description | Perpendicular shape anisotropy (PSA) and double magnetic tunnel junctions (DMTJs) offer practical solutions to downscale spin-transfer-torque Magnetic Random-Access Memory (STT-MRAM) beyond 20 nm technology nodes, while retaining their thermal stability and reducing critical currents applied. However, as these modern devices become smaller and three-dimensionally (3D) complex, our understanding of their functional magnetic behavior is often indirect, relying on magnetoresistance measurements and micromagnetic modeling. In this paper, we review recent work that was performed on these structures using a range of advanced electron microscopy techniques, focusing on aspects specific to the 3D and nanoscale nature of such elements. We present the methodology for the systematic transfer of individual SST-MRAM nano-pillars from large-scale arrays to image their magnetic configurations directly using off-axis electron holography. We show that improved phase sensitivity through stacking of electron holograms can be used to image subtle variations in DMTJs and the thermal stability of <20 nm PSA-STT-MRAM nano-pillars during in situ heating. The experimental practicalities, benefits, and limits of using electron holography for the analysis of MRAM devices are discussed, unlocking practical pathways for direct imaging of the functional magnetic performance of these systems with high spatial resolution and sensitivity. |
| first_indexed | 2024-12-11T18:36:39Z |
| format | Article |
| id | doaj.art-f18affcd38e1400d918d6ae237b98a7e |
| institution | Directory Open Access Journal |
| issn | 2166-532X |
| language | English |
| last_indexed | 2024-12-11T18:36:39Z |
| publishDate | 2022-06-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | APL Materials |
| spelling | doaj.art-f18affcd38e1400d918d6ae237b98a7e2022-12-22T00:54:45ZengAIP Publishing LLCAPL Materials2166-532X2022-06-01106061104061104-1110.1063/5.0096761Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devicesTrevor P. Almeida0Alvaro Palomino1Steven Lequeux2Victor Boureau3Olivier Fruchart4Ioan Lucian Prejbeanu5Bernard Dieny6David Cooper7University Grenoble Alpes, CEA, Leti, F-38000 Grenoble, FranceUniversity Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, 38000 Grenoble, FranceUniversity Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, 38000 Grenoble, FranceInterdisciplinary Center for Electron Microscopy, EPFL, CH-1015 Lausanne, SwitzerlandUniversity Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, 38000 Grenoble, FranceUniversity Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, 38000 Grenoble, FranceUniversity Grenoble Alpes, CEA, CNRS, Grenoble INP, SPINTEC, 38000 Grenoble, FranceUniversity Grenoble Alpes, CEA, Leti, F-38000 Grenoble, FrancePerpendicular shape anisotropy (PSA) and double magnetic tunnel junctions (DMTJs) offer practical solutions to downscale spin-transfer-torque Magnetic Random-Access Memory (STT-MRAM) beyond 20 nm technology nodes, while retaining their thermal stability and reducing critical currents applied. However, as these modern devices become smaller and three-dimensionally (3D) complex, our understanding of their functional magnetic behavior is often indirect, relying on magnetoresistance measurements and micromagnetic modeling. In this paper, we review recent work that was performed on these structures using a range of advanced electron microscopy techniques, focusing on aspects specific to the 3D and nanoscale nature of such elements. We present the methodology for the systematic transfer of individual SST-MRAM nano-pillars from large-scale arrays to image their magnetic configurations directly using off-axis electron holography. We show that improved phase sensitivity through stacking of electron holograms can be used to image subtle variations in DMTJs and the thermal stability of <20 nm PSA-STT-MRAM nano-pillars during in situ heating. The experimental practicalities, benefits, and limits of using electron holography for the analysis of MRAM devices are discussed, unlocking practical pathways for direct imaging of the functional magnetic performance of these systems with high spatial resolution and sensitivity.http://dx.doi.org/10.1063/5.0096761 |
| spellingShingle | Trevor P. Almeida Alvaro Palomino Steven Lequeux Victor Boureau Olivier Fruchart Ioan Lucian Prejbeanu Bernard Dieny David Cooper Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices APL Materials |
| title | Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices |
| title_full | Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices |
| title_fullStr | Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices |
| title_full_unstemmed | Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices |
| title_short | Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices |
| title_sort | off axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3d magnetic random access memory devices |
| url | http://dx.doi.org/10.1063/5.0096761 |
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