Impact of ultra low power and fast write operation of advanced perpendicular MTJ on power reduction for high-performance mobile CPU

Kitagawa, E.; Fujita, Shinobu; Nomura, Kumiko; Noguchi, Hiroki; Abe, Keiko; Ikegami, Kazutaka; Daibou, T.; Kato, Y.; Kamata, C.; Kashiwada, Saori; Shimomura, N.; Ito, Junichi; Yasuda, Hiroaki

doi:10.1109/iedm.2012.6479129

Cited by 79 publications

(52 citation statements)

References 5 publications

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“…22,31 We need new p-MTJs that switch rapidly with low current, high DE, and high TMR ratios. We recently succeeded in demonstrating 3-ns-pulse STT switching 32 at 50 lA in a sub-30-nm size p-MTJ (Figs. 4 and 5).…”

Section: A Fast and Low Power Stt Switching In P-mtjsmentioning

confidence: 99%

“…All 172607 (2014) components of the core are made of transistors whose speed can be as fast as 1 ps and whose operation energy can be as low as 0.1 fJ to satisfy these requirements. Our p-MTJ 32,33 with 3 ns and 90 fJ is presently the most advanced available, and its performance can hopefully be improved by one order of magnitude in the future. Nevertheless, we still cannot deny that the active performance of STT-MRAMs is far inferior to that of volatile transistor circuits in the core.…”

Section: A Dilemma With Non-volatile Memoriesmentioning

confidence: 99%

“…A DE of 61 k B T and a TMR ratio of 150% were obtained. 32,33 B. Fast reading Fast and low power STT switching p-MTJs are crucial but not sufficient to replace the SRAMs for LLCs with STTMRAMs.…”

Section: A Fast and Low Power Stt Switching In P-mtjsmentioning

confidence: 99%

See 2 more Smart Citations

Spin-transfer torque magnetoresistive random-access memory technologies for normally off computing (invited)

Ando¹,

Fujita²,

Ito³

et al. 2014

Journal of Applied Physics

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110

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Most parts of present computer systems are made of volatile devices, and the power to supply them to avoid information loss causes huge energy losses. We can eliminate this meaningless energy loss by utilizing the non-volatile function of advanced spin-transfer torque magnetoresistive random-access memory (STT-MRAM) technology and create a new type of computer, i.e., normally off computers. Critical tasks to achieve normally off computers are implementations of STT-MRAM technologies in the main memory and low-level cache memories. STT-MRAM technology for applications to the main memory has been successfully developed by using perpendicular STT-MRAMs, and faster STT-MRAM technologies for applications to the cache memory are now being developed. The present status of STT-MRAMs and challenges that remain for normally off computers are discussed.

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Section: A Fast and Low Power Stt Switching In P-mtjsmentioning

confidence: 99%

Section: A Dilemma With Non-volatile Memoriesmentioning

confidence: 99%

See 1 more Smart Citation

Spin-transfer torque magnetoresistive random-access memory technologies for normally off computing (invited)

Ando¹,

Fujita²,

Ito³

et al. 2014

Journal of Applied Physics

Self Cite

110

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show abstract

“…1,2 Such memories show promise to eventually replace DRAM and even SRAM in microprocessors. 3 The efficiency of the write process for STT-MRAM is constrained by the magnetic damping parameter, which dictates the rate at which angular momentum can be exchanged between the spin system and the crystal lattice. Thus, the discovery of magnetic memory materials with the lowest possible damping has become a prime concern of STT-MRAM developers.…”

Section: Introductionmentioning

confidence: 99%

Precise determination of the spectroscopic g-factor by use of broadband ferromagnetic resonance spectroscopy

Shaw

Nembach

Silva

et al. 2013

Journal of Applied Physics

130

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We demonstrate that the spectroscopic g−factor can be determined with high precision and accuracy by broadband ferromagnetic resonance measurements and applying an asymptotic analysis to the data. Spectroscopic data used to determine the g−factor is always obtained over a finite range of frequencies, which can result in significant errors in the fitted values of the spectroscopic g−factor. We show that by applying an asymptotic analysis to broadband datasets, precise values of the intrinsic g−factor can be determined with errors well below 1 %, even when the exact form of the Kittel equation (which describes the relationship between the frequency and resonance field) is unknown. We demonstrate this methodology with measured data obtained for sputtered Ni 80 Fe 20 ("Permalloy") thin films of varied thicknesses, where we determine the bulk g−factor value to be 2.109 ± 0.003. Such an approach is further validated by application to simulated data that includes both noise and an anisotropy that is not included in the Kittel equation that was used in the analysis. Finally, we show a correlation of thickness and interface structure to the magnitude of the asymptotic behavior, which provide insight into additional mechanisms that may induce deviations from the Kittel equation.2

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“…Consequently, the upper limit for MTJ voltage, or equivalently, the maximum achievable write-speed, is determined by the tunnel barrier reliability. One approach to address such reliability issues is to design the MTJ with lower critical switching current [1][2][3]5,6 . However, when switching current is lowered, the read current must also reduce in order to prevent disturbfailures (accidental write during read) 3,5,6 .…”

mentioning

confidence: 99%

DSH-MRAM: Differential Spin Hall MRAM for On-Chip Memories

Kim

Choday

Roy

2013

IEEE Electron Device Lett.

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A new device structure for spin transfer torque based magnetic random access memory is proposed for on-chip memory applications. Our device structure exploits spin Hall effect to create a differential memory cell that exhibits fast and energy-efficient write operation.Moreover, due to inherently differential device structure, fast and reliable read operation can be performed. Our simulation study shows 10X improvement in write energy over the standard 1T1R STT-MRAM memory cell, and 1.6X faster read operation compared to single-ended sensing (as in standard 1T1R STT-MRAMs). The bit-cell characteristics are promising for high performance on-chip memory applications.

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Impact of ultra low power and fast write operation of advanced perpendicular MTJ on power reduction for high-performance mobile CPU

Cited by 79 publications

References 5 publications

Spin-transfer torque magnetoresistive random-access memory technologies for normally off computing (invited)

Spin-transfer torque magnetoresistive random-access memory technologies for normally off computing (invited)

Precise determination of the spectroscopic g-factor by use of broadband ferromagnetic resonance spectroscopy

DSH-MRAM: Differential Spin Hall MRAM for On-Chip Memories

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