Temperature Dependence of Critical Device Parameters in 1 Gb Perpendicular Magnetic Tunnel Junction Arrays for STT-MRAM

Park, C.; Kan, Jimmy J.; Ching, Chi; Ahn, Jaehwan; Xue, Lin; Wang, R.; Kontos, A.; Liang, Shuai; Bangar, Mangesh A.; Chen, H.; Hassan, Sajjad; Kim, Sanghoek; Pakala, Mahendra; Kang, Sungwon

doi:10.1109/tmag.2016.2615816

Cited by 13 publications

(10 citation statements)

References 8 publications

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“…With TMR = 300%, >99.5% accuracy is maintained from 300 to 340 K (67 • C), while with TMR = 200%, this is true up to 330 K (57 • C). We note that although we have treated the TMR as a fixed parameter, it is also prone to degrade with temperature, with an absolute decrease by ∼20% reported in [41] and [42] from room temperature to 85 • C.…”

Section: E Sensitivity To Temperaturementioning

confidence: 99%

Energy and Performance Benchmarking of a Domain Wall-Magnetic Tunnel Junction Multibit Adder

Xiao

Marinella

Bennett

et al. 2019

IEEE J. Explor. Solid-State Comput. Devices Circuits

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The domain-wall (DW)-magnetic tunnel junction (MTJ) device implements universal Boolean logic in a manner that is naturally compact and cascadable. However, an evaluation of the energy efficiency of this emerging technology for standard logic applications is still lacking. In this article, we use a previously developed compact model to construct and benchmark a 32-bit adder entirely from DW-MTJ devices that communicates with DW-MTJ registers. The results of this large-scale design and simulation indicate that while the energy cost of systems driven by spin-transfer torque (STT) DW motion is significantly higher than previously predicted, the same concept using spin-orbit torque (SOT) switching benefits from an improvement in the energy per operation by multiple orders of magnitude, attaining competitive energy values relative to a comparable CMOS subprocessor component. This result clarifies the path toward practical implementations of an all-magnetic processor system. INDEX TERMS Benchmarking, domain wall (DW), magnetic logic, magnetic tunnel junction (MTJ), post-CMOS logic, spintronics.

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Section: E Sensitivity To Temperaturementioning

confidence: 99%

Energy and Performance Benchmarking of a Domain Wall-Magnetic Tunnel Junction Multibit Adder

Xiao

Marinella

Bennett

et al. 2019

IEEE J. Explor. Solid-State Comput. Devices Circuits

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“…Note that M x , M y , and M z are the normalized magnetization with respect to M s . Both M s and K i are temperature-dependent reportedly [34], [35], and the models are given by [36], [37]…”

Section: Llg-based Physical Modelmentioning

confidence: 99%

“…The coefficient β in Bloch's law is 1.73 from the experimental data [36]. The coefficient η is fit by the temperature variation rate of thermal stability factor ( ) [34]. The shape-dependent demagnetizing factors of a ferromagnetic cylinder are given by [38]…”

Section: Llg-based Physical Modelmentioning

confidence: 99%

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Write Margin Analysis of Spin–Orbit Torque Switching Using Field-Assisted Method

Tsou

Chiu

Shih

et al. 2019

IEEE J. Explor. Solid-State Comput. Devices Circuits

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Switching dynamics of perpendicular magnetic tunnel junction (MTJ) driven by spin-orbit torque (SOT) are investigated by the Landau-Lifshitz-Gilbert (LLG)-based physical model considering the temperature dependence. The field-assisted switching method is proposed to develop the reliable sub-ns writing of SOT-magnetoresistive random-access memory (SOT-MRAM) by removing the plateau time. The conventional method of SOT-MTJ requires the large write current, leading to the area increase of access transistors and the penalty of memory density. The write current and the switching time of SOT-MTJ can be efficiently reduced at the same time by our field-assisted method using the enhanced magnetic field. The magnetic field can be provided by the Co magnetic hard mask above the MTJ. Considering an SOT-MRAM array, the surrounded Co metals have the insignificant influence of stray magnetic field on an MTJ at the center. With the write time of 0.2 ns, the 60% reduction of write current is achieved by our field-assisted method compared to the conventional method. The required write current for the SOT switching decreases with the increasing temperature due to the lowering of thermal stability factor. The write Shmoo plots are further analyzed to calculate the write current margin at the various working temperature. The write time of 0.2 ns exhibits the narrow margin of write current (2.6 µA) in the temperature range from 25 • C to 85 • C, while the write time of 0.8 ns has the wide write margin of 102 µA. The switching behavior and the write margin are also sensitive to the magnetic field. INDEX TERMS Failure analysis, magnetic memory, magnetic tunnel junction (MTJ), spin-orbit torque (SOT), spintronics.

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“…5 Basic device functions such as reading, writing, and data retention of the p-MTJ devices vary with operating temperature. 6 The fundamental reasons for the variation are the change in the intrinsic ferromagnetic properties of the free layer (FL) and the transport properties through the MgO tunnel barrier. 7,8 Apart from these, the magneto-static fields generated from the adjacent magnetic layers, i.e., the reference layer (RL) and the hard layer (HL), act as additional factors to change the p-MTJ performance.…”

mentioning

confidence: 99%

Impact of operating temperature on the electrical and magnetic properties of the bottom-pinned perpendicular magnetic tunnel junctions

Kim

Rao

et al. 2018

Applied Physics Letters

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Analogous device parameters in both the parallel (P) and anti-parallel (AP) states ensure a symmetric spin-transfer-torque magnetic random-access memory operation scheme. In this study, however, we observe an increasing asymmetry in the performance metrics with operating temperature of the bottom-pinned perpendicular magnetic tunnel junction (p-MTJ) devices. A temperature-dependent increase in the contribution of the stray field is observed in the tunneling magnetoresistance loop analysis. The switching current for P-to-AP decreases by 30% in the thermally activated switching regime by increasing the temperature from 300 K to 400 K, while it remains similar for AP-to-P. In addition, with the same temperature range, the thermal stability factor for the P state decreases 20% more than that for the AP state. We attribute those observations to the increase in the overcompensation of the stray field from the synthetic anti-ferromagnet structure. Saturation magnetization (MS) of the [Co/Pt]x-based multilayers is much less affected by temperature [MS(400 K)/MS(300 K) = 97%] compared to that of the CoFeB-based multilayers (88%). Such an impact can be more severe during the electrical switching process due to the Joule heating effect. These results suggest that, to understand and to evaluate the performance in a wide range of temperatures, it is crucial to consider the contribution of the entire magnetic components in the p-MTJ stack.

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Temperature Dependence of Critical Device Parameters in 1 Gb Perpendicular Magnetic Tunnel Junction Arrays for STT-MRAM

Cited by 13 publications

References 8 publications

Energy and Performance Benchmarking of a Domain Wall-Magnetic Tunnel Junction Multibit Adder

Energy and Performance Benchmarking of a Domain Wall-Magnetic Tunnel Junction Multibit Adder

Write Margin Analysis of Spin–Orbit Torque Switching Using Field-Assisted Method

Impact of operating temperature on the electrical and magnetic properties of the bottom-pinned perpendicular magnetic tunnel junctions

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