Spin Torque Switching of Perpendicularly Magnetized CoFeB-Based Tunnel Junctions With High Thermal Tolerance

Yamane, K.; Higo, Y.; Uchida, Hiroyuki; Nanba, Yuji; Sasaki, Satoshi; Ohmori, Hiroyuki; Bessho, K.; Hosomi, Masanori

doi:10.1109/tmag.2013.2246141

Cited by 26 publications

(14 citation statements)

References 15 publications

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“…[1][2][3][4][5][6][7]12 In face of the increasing static power dissipation of CMOS technology at smaller nodes, it is also highly desirable to further integrate embedded MeRAM into CMOS logic circuits to achieve non-volatile electronic systems with low standby power and instant-on operation capability. 13,14 However, in the commonly used TajCoFeBjMgO system, the PMA and TMR cannot be sustained when annealing temperatures above 400 C are used, 15,16 making it incompatible with advanced CMOS back-end-of-line processes, where the low-k dielectrics used between interconnects require a thermal budget over 400 C. 17,18 Several works have recently explored MTJs with improved thermally stable TMR and PMA for spin-transfer torque magnetic random access memory (STT-MRAM) applications, primarily by blocking or eliminating Ta diffusion under high temperatures. [17][18][19][20] Nevertheless, for VCMA-based embedded memory applications, it is critical to develop new material systems that can also provide thermally stable VCMA after annealing at 400 C.…”

Section: Thermally Stable Voltage-controlled Perpendicular Magnetic Amentioning

confidence: 99%

Thermally stable voltage-controlled perpendicular magnetic anisotropy in Mo|CoFeB|MgO structures

et al. 2015

Applied Physics Letters

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We study voltage-controlled magnetic anisotropy (VCMA) and other magnetic properties in annealed MojCoFeBjMgO layered structures. The interfacial perpendicular magnetic anisotropy (PMA) is observed to increase with annealing over the studied temperature range, and a VCMA coefficient of about 40 fJ/V-m is sustained after annealing at temperatures as high as 430 C. Ab initio electronic structure calculations of interfacial PMA as a function of strain further show that strain relaxation may lead to the increase of interfacial PMA at higher annealing temperatures. Measurements also show that there is no significant VCMA and interfacial PMA dependence on the CoFeB thickness over the studied range, which illustrates the interfacial origin of the anisotropy and its voltage dependence, i.e., the VCMA effect. The high thermal annealing stability of MojCoFeBjMgO structures makes them compatible with advanced CMOS back-end-of-line processes, and will be important for integration of magnetoelectric random access memory into on-chip embedded applications. V

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Section: Thermally Stable Voltage-controlled Perpendicular Magnetic Amentioning

confidence: 99%

Thermally stable voltage-controlled perpendicular magnetic anisotropy in Mo|CoFeB|MgO structures

et al. 2015

Applied Physics Letters

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“…Current densities as low as 3-6 Â 10 10 A=m 2 were reported for 2-3 nm thick Ta using a quasi-DC current [33]. Considering this current density and a 2 nm thick, 50 nm wide Ta line, currents as low as 3-6 mA could be used, already competing with the best results reported for the STT-MRAM [9], [41], [42]. Moreover, only few materials have been tested until now and there is certainly plenty of room for improvement on this side.…”

Section: Introductionmentioning

confidence: 95%

Ultra-Fast and High-Reliability SOT-MRAM: From Cache Replacement to Normally-Off Computing

Prenat

Jabeur

Vanhauwaert

et al. 2016

IEEE Trans. Multi-Scale Comp. Syst.

151

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This paper deals with a new MRAM technology whose writing scheme relies on the Spin Orbit Torque (SOT). Compared to Spin Transfer Torque (STT) MRAM, it offers a very fast switching, a quasi-infinite endurance and improves the reliability by solving the issue of "read disturb", thanks to separate reading and writing paths. These properties allow introducing SOT at all-levels of the memory hierarchy of systems and adressing applications which could not be easily implemented by STT-MRAM. We present this emerging technology and a full design framework, allowing to design and simulate hybrid CMOS/SOT complex circuits at any level of abstraction, from device to system. The results obtained are very promising and show that this technology leads to a reduced power consumption of circuits without notable penalty in terms of performance.

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“…In particular, the structure design of a p-MTJ spin valve (i.e., a p-MTJ spin valve with a nanoscale-thick top free layer or a p-MTJ spin valve with a nanoscale-thick bottom free layer) has intensively been studied to achieve a higher TMR ratio at the back end of line (BEOL) temperature of 400 °C [ 7 – 10 ]. Note that the BEOL temperature of 400 °C is required to integrate memory cells [ 11 ]. In addition, for a p-MTJ spin valve with a nanoscale-thick top free layer, the CoFeB free layer is located above the synthetic antiferromagnetic (SyAF) layer in a p-MTJ spin valve, while for a p-MTJ spin valve with a nanoscale-thick bottom free layer, the CoFeB free layer is located below the SyAF layer in a p-MTJ spin valve.…”

Section: Introductionmentioning

confidence: 99%

Tunneling-Magnetoresistance Ratio Comparison of MgO-Based Perpendicular-Magnetic-Tunneling-Junction Spin Valve Between Top and Bottom Co2Fe6B2 Free Layer Structure

Lee

Shim

et al. 2016

Nanoscale Res Lett

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For the perpendicular-magnetic-tunneling-junction (p-MTJ) spin valve with a nanoscale-thick bottom Co2Fe6B2 free layer ex situ annealed at 400 °C, which has been used as a common p-MTJ structure, the Pt atoms of the Pt buffer layer diffused into the MgO tunneling barrier. This transformed the MgO tunneling barrier from a body-centered cubic (b.c.c) crystallized layer into a mixture of b.c.c, face-centered cubic, and amorphous layers and rapidly decreased the tunneling-magnetoresistance (TMR) ratio. The p-MTJ spin valve with a nanoscale-thick top Co2Fe6B2 free layer could prevent the Pt atoms diffusing into the MgO tunneling barrier during ex situ annealing at 400 °C because of non-necessity of a Pt buffer layer, demonstrating the TMR ratio of ~143 %.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-016-1637-9) contains supplementary material, which is available to authorized users.

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Spin Torque Switching of Perpendicularly Magnetized CoFeB-Based Tunnel Junctions With High Thermal Tolerance

Cited by 26 publications

References 15 publications

Thermally stable voltage-controlled perpendicular magnetic anisotropy in Mo|CoFeB|MgO structures

Thermally stable voltage-controlled perpendicular magnetic anisotropy in Mo|CoFeB|MgO structures

Ultra-Fast and High-Reliability SOT-MRAM: From Cache Replacement to Normally-Off Computing

Tunneling-Magnetoresistance Ratio Comparison of MgO-Based Perpendicular-Magnetic-Tunneling-Junction Spin Valve Between Top and Bottom Co2Fe6B2 Free Layer Structure

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