Heavy-Ion-Induced Displacement Damage Effects in Magnetic Tunnel Junctions with Perpendicular Anisotropy

T. Patrick Xiao; Christopher H. Bennett; Frederick B. Mancoff; Jack E. Manuel; David R. Hughart; Robin B. Jacobs-Gedrim; Edward S. Bielejec; Gyorgy Vizkelethy; Jijun Sun; Sanjeev Aggarwal; Reza Arghavani; Matthew J. Marinella

doi:10.1109/TNS.2021.3057348

Heavy-Ion-Induced Displacement Damage Effects in Magnetic Tunnel Junctions with Perpendicular Anisotropy

T. Patrick Xiao, Christopher H. Bennett, Frederick B. Mancoff, Jack E. Manuel, David R. Hughart, Robin B. Jacobs-Gedrim, Edward S. Bielejec, Gyorgy Vizkelethy, Jijun Sun, Sanjeev Aggarwal, Reza Arghavani, Matthew J. Marinella

Research output: Contribution to journal › Article › peer-review

14 Scopus citations

Abstract

We evaluate the resilience of CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) with perpendicular magnetic anisotropy (PMA) to displacement damage induced by heavy-ion irradiation. MTJs were exposed to 3-MeV Ta2+ ions at different levels of ion beam fluence spanning five orders of magnitude. The devices remained insensitive to beam fluences up to $10^{11}$ ions/cm2, beyond which a gradual degradation in the device magnetoresistance, coercive magnetic field, and spin-transfer-torque (STT) switching voltage were observed, ending with a complete loss of magnetoresistance at very high levels of displacement damage (>0.035 displacements per atom). The loss of magnetoresistance is attributed to structural damage at the MgO interfaces, which allows electrons to scatter among the propagating modes within the tunnel barrier and reduces the net spin polarization. Ion-induced damage to the interface also reduces the PMA. This study clarifies the displacement damage thresholds that lead to significant irreversible changes in the characteristics of STT magnetic random access memory (STT-MRAM) and elucidates the physical mechanisms underlying the deterioration in device properties.

Original language	English (US)
Article number	9349507
Pages (from-to)	581-587
Number of pages	7
Journal	IEEE Transactions on Nuclear Science
Volume	68
Issue number	5
DOIs	https://doi.org/10.1109/TNS.2021.3057348
State	Published - May 2021
Externally published	Yes

Keywords

Displacement damage
heavy-ion irradiation
magnetic random access memory (MRAM)
magnetic tunnel junction (MTJ)
nonvolatile memory
perpendicular magnetic anisotropy (PMA)
spin-transfer-torque MRAM (STT-MRAM)

ASJC Scopus subject areas

Nuclear and High Energy Physics
Nuclear Energy and Engineering
Electrical and Electronic Engineering

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10.1109/TNS.2021.3057348

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Xiao, T. P., Bennett, C. H., Mancoff, F. B., Manuel, J. E., Hughart, D. R., Jacobs-Gedrim, R. B., Bielejec, E. S., Vizkelethy, G., Sun, J., Aggarwal, S., Arghavani, R., & Marinella, M. J. (2021). Heavy-Ion-Induced Displacement Damage Effects in Magnetic Tunnel Junctions with Perpendicular Anisotropy. IEEE Transactions on Nuclear Science, 68(5), 581-587. Article 9349507. https://doi.org/10.1109/TNS.2021.3057348

Xiao, TP, Bennett, CH, Mancoff, FB, Manuel, JE, Hughart, DR, Jacobs-Gedrim, RB, Bielejec, ES, Vizkelethy, G, Sun, J, Aggarwal, S, Arghavani, R & Marinella, MJ 2021, 'Heavy-Ion-Induced Displacement Damage Effects in Magnetic Tunnel Junctions with Perpendicular Anisotropy', IEEE Transactions on Nuclear Science, vol. 68, no. 5, 9349507, pp. 581-587. https://doi.org/10.1109/TNS.2021.3057348

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abstract = "We evaluate the resilience of CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) with perpendicular magnetic anisotropy (PMA) to displacement damage induced by heavy-ion irradiation. MTJs were exposed to 3-MeV Ta2+ ions at different levels of ion beam fluence spanning five orders of magnitude. The devices remained insensitive to beam fluences up to $10^{11}$ ions/cm2, beyond which a gradual degradation in the device magnetoresistance, coercive magnetic field, and spin-transfer-torque (STT) switching voltage were observed, ending with a complete loss of magnetoresistance at very high levels of displacement damage (>0.035 displacements per atom). The loss of magnetoresistance is attributed to structural damage at the MgO interfaces, which allows electrons to scatter among the propagating modes within the tunnel barrier and reduces the net spin polarization. Ion-induced damage to the interface also reduces the PMA. This study clarifies the displacement damage thresholds that lead to significant irreversible changes in the characteristics of STT magnetic random access memory (STT-MRAM) and elucidates the physical mechanisms underlying the deterioration in device properties.",

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AU - Xiao, T. Patrick

AU - Bennett, Christopher H.

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AU - Manuel, Jack E.

AU - Hughart, David R.

AU - Jacobs-Gedrim, Robin B.

AU - Bielejec, Edward S.

AU - Vizkelethy, Gyorgy

AU - Sun, Jijun

AU - Aggarwal, Sanjeev

AU - Arghavani, Reza

AU - Marinella, Matthew J.

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AB - We evaluate the resilience of CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) with perpendicular magnetic anisotropy (PMA) to displacement damage induced by heavy-ion irradiation. MTJs were exposed to 3-MeV Ta2+ ions at different levels of ion beam fluence spanning five orders of magnitude. The devices remained insensitive to beam fluences up to $10^{11}$ ions/cm2, beyond which a gradual degradation in the device magnetoresistance, coercive magnetic field, and spin-transfer-torque (STT) switching voltage were observed, ending with a complete loss of magnetoresistance at very high levels of displacement damage (>0.035 displacements per atom). The loss of magnetoresistance is attributed to structural damage at the MgO interfaces, which allows electrons to scatter among the propagating modes within the tunnel barrier and reduces the net spin polarization. Ion-induced damage to the interface also reduces the PMA. This study clarifies the displacement damage thresholds that lead to significant irreversible changes in the characteristics of STT magnetic random access memory (STT-MRAM) and elucidates the physical mechanisms underlying the deterioration in device properties.

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Heavy-Ion-Induced Displacement Damage Effects in Magnetic Tunnel Junctions with Perpendicular Anisotropy

Abstract

Keywords

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