Achieving Sub-ns switching of STT-MRAM for future embedded LLC applications through improvement of nucleation and propagation switching mechanisms

Jan, Guenole; Thomas, Luc; Le, S.; Lee, Yuan-Jen; Liu, Huanlong; Zhu, Jianguo; Iwata-Harms, Jodi; Patel, Sahil; Tong, Ru-Ying; Serrano-Guisan, S.; Shen, Dongna; He, Renren; Haq, Jesmin; Teng, Jeffrey W.; Lam, Vinh; Annapragada, Rao; Wang, Yu-Jen; Zhong, Tom; Torng, Terry; Wang, Po-Kang

doi:10.1109/vlsit.2016.7573362

Cited by 16 publications

(7 citation statements)

References 2 publications

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“…Real-time switching dynamics in STT-MRAM "switching" while in previous works these two phases were combined in a single global phase called "switching" [11]. The separation is important because in reality two successive phases occur as demonstrated in [11][12][13][14]. In the first phase, the nucleation of the domain wall, during what we call in this paper the "Preswitching time", spins are accumulated in the free layer and the nucleation takes place.…”

Section: A Shows a High-resolution Transmission Electronmentioning

confidence: 96%

Real-Time Switching Dynamics in STT-MRAM

Yazigy

Postel-Pellerin

Marca

et al. 2022

IEEE J. Electron Devices Soc.

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In this paper a new experimental technique for measuring the switching dynamics and extracting the energy consumption of Spin Transfer Torque MRAM (STT-MRAM) device is presented. This technique is performed by a real-time current reading while a pulsed bias is applied. The switching from a high resistive state, anti-parallel (AP) alignment, to a low resistive state, parallel (P) alignment, is investigated as well as the impact of the cell diameter on the switching parameters. We demonstrate that preswitching and switching times and energies have a log-linear relationship with the applied voltage. Increasing the applied voltage leads to a higher spin torque on the free layer in a shorter time. This decreases the time needed to change the magnetization orientation of this layer, thus the time required before the switching occurs. We have also shown that for a given applied voltage, the smaller the cell the longer the time before switching. For low applied voltages, the preswitching time increases exponentially dominating the whole reversal time. The longer switching times can be explained by a lower Joule heating not sufficient to induce the thermally activated reversal process. This phenomenon is accentuated for smaller cells, where the heating is more significant and the time before switching is shorter than for larger cells.

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Section: A Shows a High-resolution Transmission Electronmentioning

confidence: 96%

Real-Time Switching Dynamics in STT-MRAM

Yazigy

Postel-Pellerin

Marca

et al. 2022

IEEE J. Electron Devices Soc.

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“…random access memory (MRAM) with large perpendicular magnetic anisotropy is attractive for its good scalability and high thermal stability [4,5] during fast sub-nanosecond write, [6] the required high write current density can exert severe stress on the magnetic tunnel junction (MTJ) and induce wear-out and breakdown of the MTJ barrier, [7] leading ultimately to degradation of the memory cell. Meanwhile, the shared read/write path can lead to write upon read errors.…”

Section: Energy-efficient Ultrafast Sot-mrams Based Onmentioning

confidence: 99%

“…[1] Au 0.25 Pt 0.75 is also thermally stable as indicated by the constant ρ xx and θ SH upon annealing to 400 °C. 2020, 6,1901131 The factor A ≈ exp(−d Hf /λ s,Hf ) denotes the attenuation of spin current by the Hf spacer layer (the thickness d Hf and the spin diffusion length λ s,Hf ) in between the spin Hall channel and the magnetic free layer of the magnetic tunnel junction. Electron.…”

Section: Direct Current Switchingmentioning

confidence: 99%

Energy‐Efficient Ultrafast SOT‐MRAMs Based on Low‐Resistivity Spin Hall Metal Au_0.25Pt_0.75

Zhu

Shi

et al. 2020

Adv Elect Materials

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As shown in Figure 1b-d, the SOT-MTJ devices were lithographically patterned from sputter-deposited multilayer stacks consisting of Si/SiO 2 /Ta 1/Au 0.25 Pt 0.75 5/Hf 0.5/ Fe 0.6 Co 0.2 B 0.2Many key electronic technologies (e.g., large-scale computing, machine learning, and superconducting electronics) require new memories that are at the same time fast, reliable, energy-efficient, and of low-impedance, which has remained a challenge. Nonvolatile magnetoresistive random access memories (MRAMs) driven by spin-orbit torques (SOTs) have promise to be faster and more energy-efficient than conventional semiconductor and spin-transfer-torque magnetic memories. It is reported that the spin Hall effect of low-resistivity Au 0.25 Pt 0.75 thin films enables ultrafast antidamping-torque switching of SOT-MRAM devices for current pulse widths as short as 200 ps. If combined with industrial-quality lithography and already-demonstrated interfacial engineering, an optimized MRAM cell based on Au 0.25 Pt 0.75 can have energy-efficient, ultrafast, and reliable switching, for example, a write energy of <1 fJ (<50 fJ) for write error rate of 50% (<10 −5 ) for 1 ns pulses. The antidamping torque switching of the Au 0.25 Pt 0.75 devices is ten times faster than expected from a rigid macrospin model, most likely because of the fast micromagnetics due to the enhanced nonuniformity within the free layer. The feasibility of Au 0.25 Pt 0.75 -based SOT-MRAMs as a candidate for ultrafast, reliable, energy-efficient, low-impedance, and unlimited-endurance memory is demonstrated.

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“…Note that the TRNG pulse-width can be much faster than 1 µs used in Figs. 2 and 4, since sub-nanosecond switching was reported for STT-MRAM [29]. A shorter time might allow for a higher TRNG throughput and a smaller Q n , hence a correspondingly smaller area of the integrating capacitor.…”

Section: Stt-mram Based Trngmentioning

confidence: 99%

Random Number Generation by Differential Read of Stochastic Switching in Spin-Transfer Torque Memory

Carboni

Chen

Siddik

et al. 2018

IEEE Electron Device Lett.

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The true random number generator (TRNG) is a key enabling technology for cryptography and hardware authentication, which are becoming essential features in the era of the internet of things (IoT). Here, we present a novel TRNG concept based on the stochastic switching in spin-transfer torque magnetic random access memory (STT-MRAM). The new methodology relies on the STT-MRAM switching variations affecting the current response under applied rectangular or triangular pulses. Random numbers are extracted from the differential read of the integrated current across 2 stochastic switching cycles. The proposed concept passes all tests in the NIST SP-800-22 suite with no post-processing, thus supporting STT-MRAM as a promising technology for data/hardware security in the IoT.

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Achieving Sub-ns switching of STT-MRAM for future embedded LLC applications through improvement of nucleation and propagation switching mechanisms

Cited by 16 publications

References 2 publications

Real-Time Switching Dynamics in STT-MRAM

Real-Time Switching Dynamics in STT-MRAM

Energy‐Efficient Ultrafast SOT‐MRAMs Based on Low‐Resistivity Spin Hall Metal Au_0.25Pt_0.75

Random Number Generation by Differential Read of Stochastic Switching in Spin-Transfer Torque Memory

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Achieving Sub-ns switching of STT-MRAM for future embedded LLC applications through improvement of nucleation and propagation switching mechanisms

Cited by 16 publications

References 2 publications

Real-Time Switching Dynamics in STT-MRAM

Real-Time Switching Dynamics in STT-MRAM

Energy‐Efficient Ultrafast SOT‐MRAMs Based on Low‐Resistivity Spin Hall Metal Au0.25Pt0.75

Random Number Generation by Differential Read of Stochastic Switching in Spin-Transfer Torque Memory

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Energy‐Efficient Ultrafast SOT‐MRAMs Based on Low‐Resistivity Spin Hall Metal Au_0.25Pt_0.75