A 14 nm Embedded STT-MRAM CMOS Technology

Edelstein, D.; Rizzolo, Michael; Sil, Devika; Dutta, Ashim; DeBrosse, J.; Wordeman, M.R.; Arceo, Abraham; Chu, In Chang; Demarest, J.; Edwards, Eric R. J.; Evarts, Eric R.; Fullam, Jennifer; Gasasira, Arthur; Hu, G.; Iwatake, M.; Johnson, R.C.; Katragadda, Veenadhar; Levin, T. M.; Li, J.; Liu, Y.; Long, Christopher; Maffitt, T.; McDermott, Steven; Mehta, S.; Mehta, Virat; Metzler, Dominik; Morillo, Jaime; Nakamura, Yohei; Nguyen, S.; Nieves, P.; Pai, Vijay S.; Patlolla, R.; Pujari, R.; Southwick, Richard G.; Standaert, T.; Straten, O. van der; Wu, Heng; Yang, Chen-Chi; Houssameddine, D.; Slaughter, J. M.; Worledge, D. C.

doi:10.1109/iedm13553.2020.9371922

Cited by 35 publications

(12 citation statements)

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“…5 Université de Lorraine, CNRS, IJL, Nancy, France. 6 Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France. *Corresponding author.…”

Section: Introductionunclassified

“…In recent years, spintronics (1-3) has gained considerable attention and shows great promise for low-power, nonvolatile memory technology. While magnetic memory devices based on spin-transfer torque (STT) have already been introduced to the market (4)(5)(6), they still present some challenges such as device lifetime (10 10 write cycles limited by tunnel barrier breakdown), relatively slow switching speed and the write error rate (due to the stochastic thermal fluctuation induced switching initiation), which are affecting its performance compared to the state-of-the-art semiconductor memory devices (3,4). Spin-orbit torque (SOT)-based devices, on the other hand, are expected to largely overcome these problems.…”

Section: Introductionmentioning

confidence: 99%

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Picosecond spin-orbit torque–induced coherent magnetization switching in a ferromagnet

Polley,

Pattabi,

Rastogi

et al. 2023

Sci. Adv.

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Electrically controllable nonvolatile magnetic memories show great potential for the replacement of conventional semiconductor-based memory technologies. Here, we experimentally demonstrate ultrafast spin-orbit torque (SOT)–induced coherent magnetization switching dynamics in a ferromagnet. We use an ultrafast photoconducting switch and a coplanar strip line to generate and guide a ~9-picosecond electrical pulse into a heavy metal/ferromagnet multilayer to induce ultrafast SOT. We then use magneto-optical probing to investigate the magnetization dynamics with sub-picosecond resolution. Ultrafast heating by the approximately 9 picosecond current pulse induces a thermal anisotropy torque which, in combination with the damping-like torque, coherently rotates the magnetization to obtain zero-crossing of magnetization in ~70 picoseconds. A macro-magnetic simulation coupled with an ultrafast heating model agrees well with the experiment and suggests coherent magnetization switching without any incubation delay on an unprecedented time scale. Our work proposes a unique magnetization switching mechanism toward markedly increasing the writing speed of SOT magnetic random-access memory devices.

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“…5 Université de Lorraine, CNRS, IJL, Nancy, France. 6 Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France. *Corresponding author.…”

Section: Introductionunclassified

Section: Introductionmentioning

confidence: 99%

Picosecond spin-orbit torque–induced coherent magnetization switching in a ferromagnet

Polley,

Pattabi,

Rastogi

et al. 2023

Sci. Adv.

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“…Furthermore, the recent developments of embedding memory elements in the early back-end-of-line (BEOL) of the manufacturing process demand advanced materials and dimensional metrology very late in the process that was previously not required. 1 In particular, there is now a significant need for optical critical dimension (OCD) metrology during these later stages of device manufacturing. 2 The most advanced back-end memory devices are embedded between the first and second metal levels on top of frontend complementary metal-oxide-semiconductor (CMOS) logic.…”

Section: Introductionmentioning

confidence: 99%

“…4 In this paper, scatterometry challenges are discussed, and one approach that helps to overcome some of the shortcomings of the model-based optical technique is presented in more detail. VTS capabilities for three different BEOL examples are demonstrated: (i) measuring critical dimensions (CDs) of a first metal level on top of nanosheet gate-all-around (NS-GAA) transistor structures, 5,6 (ii) measuring the thickness of an interlayer dielectric (ILD) above embedded memory in the active area, 1 and (iii) measuring CDs of trenches on top of tall stacks in the micrometer range comprising many layered dielectrics. In addition, the significantly improved prediction capabilities of VTS trained machine learning models over traditional approaches are shown.…”

Section: Introductionmentioning

confidence: 99%

Spectral interferometry for fully integrated device metrology

Schmidt¹,

Medikonda²,

Rizzolo³

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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A spectral interferometry technique called vertical travelling scatterometry (VTS) is introduced, demonstrated, and discussed. VTS utilizes unique information from spectral interferometry and enables solutions for applications that are infeasible with traditional scatterometry approaches. The technique allows for data filtering related to spectral information from buried layers, which can then be ignored in the optical model. Therefore, using VTS, selective analyses of the topmost part of an arbitrarily complex stack are possible within a single metrology step. This methodology helps to overcome geometrical complexities and allows for focusing on parameters of interest through dramatically simplified optical modeling. Such model simplifications are specifically desired for back-end-of-line applications. Three examples are monitored discussed: (i) the critical dimensions (CDs) of a first metal level on top of nanosheet gate-all-around transistor structures, (ii) the thickness of an interlayer dielectric above embedded memory in the active area, and (iii) the CDs of trenches on top of tall stacks in the micrometer range comprising many layered dielectrics. It was found that, in all three cases, data filtering through VTS allowed for a simple optical model capable of delivering parameters of interest. The validity and accuracy of the VTS solution results were confirmed by extensive reference metrology obtained by traditional scatterometry, scanning electron microscopy, and transmission electron microscopy. Furthermore, it was shown that machine learning models trained with VTS filtered data can converge to a robust solution with a smaller dataset compared with models training with traditional scatterometry data.

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“…HE magnetic tunnel junction (MTJ) has been widely used in non-volatile random access memory, logic devices, and unconventional computing because of its benefits, e.g., nanosecond speed operation, scalability, thermal stability, high endurance, and compatibility with CMOS [1][2][3][4][5]. More recently, the MTJ is being studied as a probabilistic-bit circuit element due to its thermally-driven magnetization dynamics [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Random Bitstream Generation Using Voltage-Controlled Magnetic Anisotropy and Spin Orbit Torque Magnetic Tunnel Junctions

Liu

Kwon

Bessler

et al. 2022

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

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Probabilistic computing using random number generators (RNGs) can leverage the inherent stochasticity of nanodevices for system-level benefits. Device candidates for this application need to produce highly random "coinflips" while also having tunable biasing of the coin. The magnetic tunnel junction (MTJ) has been studied as an RNG due to its thermally-driven magnetization dynamics, often using spin transfer torque (STT) current amplitude to control the random switching of the MTJ free layer magnetization, here called the stochastic write method. There are additional knobs to control the MTJ-RNG, including voltage-controlled magnetic anisotropy (VCMA) and spin orbit torque (SOT), and there is need to more systematically study and compare these methods. We build an analytical model of the MTJ to characterize using VCMA and SOT to generate random bit streams. The results show that both methods produce high quality, uniformly distributed bitstreams. Biasing the bitstreams using either STT current or an applied magnetic field shows a sigmoidal distribution vs. bias amplitude for both VCMA and SOT, compared to less sigmoidal for stochastic write. The energy consumption per sample is calculated to be 0.1 pJ (SOT), 1 pJ (stochastic write), and 20 pJ (VCMA), revealing the potential energy benefit of using SOT and showing using VCMA may require higher damping materials. The generated bitstreams are then applied to two tasks: generating an arbitrary probability distribution and using the MTJ-RNGs as stochastic neurons to perform simulated annealing, where both VCMA and SOT methods show the ability to effectively minimize the system energy with small delay and low energy. These results show the flexibility of the MTJ as a true RNG and elucidate design parameters for optimizing the device operation for applications.

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A 14 nm Embedded STT-MRAM CMOS Technology

Cited by 35 publications

References 0 publications

Picosecond spin-orbit torque–induced coherent magnetization switching in a ferromagnet

Picosecond spin-orbit torque–induced coherent magnetization switching in a ferromagnet

Spectral interferometry for fully integrated device metrology

Random Bitstream Generation Using Voltage-Controlled Magnetic Anisotropy and Spin Orbit Torque Magnetic Tunnel Junctions

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