COAST

Correlated material assisted STT MRAMs for optimized read operation

Ahmedullah Aziz, Nikhil Shukla, Suman Datta, Sumeet Kumar Gupta

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    7 Citations (Scopus)

    Abstract

    We present a novel technique for optimizing the read operation of spin-transfer torque (STT) MRAMs by employing a correlated material in conjunction with a magnetic tunnel junction (MTJ). The design of the proposed memory cell is based on exploiting the orders-of-magnitude difference in the resistance of the two phases of the correlated material (CM) and triggering operation-driven phase transitions in the CM by judiciously co-optimizing devices and the memory cell. During read, the CM operates in the metallic and insulating phases when the MTJ is in the low resistance and high resistance states, respectively. This leads to superior distinguishability, read efficiency and stability. During write, the CM operates in the metallic phase, which minimizes the impact of the CM resistance on the write speed. Our analysis shows that CM amplifies the cell tunneling magneto-resistance from 107% (for the standard STT MRAM) to 1878% (for the proposed cell) leading to 68% higher sense margin. In addition, 45% enhancement in the read disturb margin and 36% reduction in the cell read power is achieved. At the same time, the write asymmetry associated with different state transitions is mildly mitigated, leading to 9% reduction in the write power. This comes at a negligible cost of 4% larger write time. We also discuss the layout implications of our technique and propose the sharing of the CM amongst multiple cells. As a result of the sharing, the proposed technique incurs no area penalty.

    Original languageEnglish (US)
    Title of host publicationProceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2015
    PublisherInstitute of Electrical and Electronics Engineers Inc.
    Pages1-6
    Number of pages6
    Volume2015-September
    ISBN (Electronic)9781467380096
    DOIs
    StatePublished - Sep 21 2015
    Event20th IEEE/ACM International Symposium on Low Power Electronics and Design, ISLPED 2015 - Rome, Italy
    Duration: Jul 22 2015Jul 24 2015

    Other

    Other20th IEEE/ACM International Symposium on Low Power Electronics and Design, ISLPED 2015
    CountryItaly
    CityRome
    Period7/22/157/24/15

    Fingerprint

    Torque
    Tunnel junctions
    Tunnelling magnetoresistance
    Data storage equipment
    Phase transitions
    Costs

    All Science Journal Classification (ASJC) codes

    • Engineering(all)

    Cite this

    Aziz, A., Shukla, N., Datta, S., & Gupta, S. K. (2015). COAST: Correlated material assisted STT MRAMs for optimized read operation. In Proceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2015 (Vol. 2015-September, pp. 1-6). [7273481] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/ISLPED.2015.7273481
    Aziz, Ahmedullah ; Shukla, Nikhil ; Datta, Suman ; Gupta, Sumeet Kumar. / COAST : Correlated material assisted STT MRAMs for optimized read operation. Proceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2015. Vol. 2015-September Institute of Electrical and Electronics Engineers Inc., 2015. pp. 1-6
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    abstract = "We present a novel technique for optimizing the read operation of spin-transfer torque (STT) MRAMs by employing a correlated material in conjunction with a magnetic tunnel junction (MTJ). The design of the proposed memory cell is based on exploiting the orders-of-magnitude difference in the resistance of the two phases of the correlated material (CM) and triggering operation-driven phase transitions in the CM by judiciously co-optimizing devices and the memory cell. During read, the CM operates in the metallic and insulating phases when the MTJ is in the low resistance and high resistance states, respectively. This leads to superior distinguishability, read efficiency and stability. During write, the CM operates in the metallic phase, which minimizes the impact of the CM resistance on the write speed. Our analysis shows that CM amplifies the cell tunneling magneto-resistance from 107{\%} (for the standard STT MRAM) to 1878{\%} (for the proposed cell) leading to 68{\%} higher sense margin. In addition, 45{\%} enhancement in the read disturb margin and 36{\%} reduction in the cell read power is achieved. At the same time, the write asymmetry associated with different state transitions is mildly mitigated, leading to 9{\%} reduction in the write power. This comes at a negligible cost of 4{\%} larger write time. We also discuss the layout implications of our technique and propose the sharing of the CM amongst multiple cells. As a result of the sharing, the proposed technique incurs no area penalty.",
    author = "Ahmedullah Aziz and Nikhil Shukla and Suman Datta and Gupta, {Sumeet Kumar}",
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    Aziz, A, Shukla, N, Datta, S & Gupta, SK 2015, COAST: Correlated material assisted STT MRAMs for optimized read operation. in Proceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2015. vol. 2015-September, 7273481, Institute of Electrical and Electronics Engineers Inc., pp. 1-6, 20th IEEE/ACM International Symposium on Low Power Electronics and Design, ISLPED 2015, Rome, Italy, 7/22/15. https://doi.org/10.1109/ISLPED.2015.7273481

    COAST : Correlated material assisted STT MRAMs for optimized read operation. / Aziz, Ahmedullah; Shukla, Nikhil; Datta, Suman; Gupta, Sumeet Kumar.

    Proceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2015. Vol. 2015-September Institute of Electrical and Electronics Engineers Inc., 2015. p. 1-6 7273481.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

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    T2 - Correlated material assisted STT MRAMs for optimized read operation

    AU - Aziz, Ahmedullah

    AU - Shukla, Nikhil

    AU - Datta, Suman

    AU - Gupta, Sumeet Kumar

    PY - 2015/9/21

    Y1 - 2015/9/21

    N2 - We present a novel technique for optimizing the read operation of spin-transfer torque (STT) MRAMs by employing a correlated material in conjunction with a magnetic tunnel junction (MTJ). The design of the proposed memory cell is based on exploiting the orders-of-magnitude difference in the resistance of the two phases of the correlated material (CM) and triggering operation-driven phase transitions in the CM by judiciously co-optimizing devices and the memory cell. During read, the CM operates in the metallic and insulating phases when the MTJ is in the low resistance and high resistance states, respectively. This leads to superior distinguishability, read efficiency and stability. During write, the CM operates in the metallic phase, which minimizes the impact of the CM resistance on the write speed. Our analysis shows that CM amplifies the cell tunneling magneto-resistance from 107% (for the standard STT MRAM) to 1878% (for the proposed cell) leading to 68% higher sense margin. In addition, 45% enhancement in the read disturb margin and 36% reduction in the cell read power is achieved. At the same time, the write asymmetry associated with different state transitions is mildly mitigated, leading to 9% reduction in the write power. This comes at a negligible cost of 4% larger write time. We also discuss the layout implications of our technique and propose the sharing of the CM amongst multiple cells. As a result of the sharing, the proposed technique incurs no area penalty.

    AB - We present a novel technique for optimizing the read operation of spin-transfer torque (STT) MRAMs by employing a correlated material in conjunction with a magnetic tunnel junction (MTJ). The design of the proposed memory cell is based on exploiting the orders-of-magnitude difference in the resistance of the two phases of the correlated material (CM) and triggering operation-driven phase transitions in the CM by judiciously co-optimizing devices and the memory cell. During read, the CM operates in the metallic and insulating phases when the MTJ is in the low resistance and high resistance states, respectively. This leads to superior distinguishability, read efficiency and stability. During write, the CM operates in the metallic phase, which minimizes the impact of the CM resistance on the write speed. Our analysis shows that CM amplifies the cell tunneling magneto-resistance from 107% (for the standard STT MRAM) to 1878% (for the proposed cell) leading to 68% higher sense margin. In addition, 45% enhancement in the read disturb margin and 36% reduction in the cell read power is achieved. At the same time, the write asymmetry associated with different state transitions is mildly mitigated, leading to 9% reduction in the write power. This comes at a negligible cost of 4% larger write time. We also discuss the layout implications of our technique and propose the sharing of the CM amongst multiple cells. As a result of the sharing, the proposed technique incurs no area penalty.

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    DO - 10.1109/ISLPED.2015.7273481

    M3 - Conference contribution

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    BT - Proceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2015

    PB - Institute of Electrical and Electronics Engineers Inc.

    ER -

    Aziz A, Shukla N, Datta S, Gupta SK. COAST: Correlated material assisted STT MRAMs for optimized read operation. In Proceedings of the International Symposium on Low Power Electronics and Design, ISLPED 2015. Vol. 2015-September. Institute of Electrical and Electronics Engineers Inc. 2015. p. 1-6. 7273481 https://doi.org/10.1109/ISLPED.2015.7273481