10 nm\phi perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction with over 400°C high thermal tolerance by boron diffusion control

Honjo, Haruo; Sato, Hideo; Ikeda, Shoji; Sato, Setsuko; Watanebe, T.; Miura, Shigeto; Nasuno, T.; Noguchi, Y.; Yasuhira, M.; Tanigawa, T.; Koike, Hideaki; Muraguchi, Masahiro; Niwa, Miki; Ito, Keita; Ohno, Hideo; Endoh, Tetsuo

doi:10.1109/vlsit.2015.7223661

Cited by 24 publications

(8 citation statements)

References 4 publications

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“…To enhance thermal tolerance, simultaneously to keep high TMR ratio and low RA, the optimization on MTJ device structure has attracted lots of attention. Co/Pt multilayer-based synthetic ferromagnetic (SyF) reference layers [ 47 , 48 ] and double CoFeB/MgO interface structure [ 43 , 49 ] have proved effective to get a high TMR ratio above 400 °C required for CMOS BEOL.…”

Section: Failure Issues Due To Nanofabrication Of Magnetic Tunnel mentioning

confidence: 99%

Failure Analysis in Magnetic Tunnel Junction Nanopillar with Interfacial Perpendicular Magnetic Anisotropy

et al. 2016

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Magnetic tunnel junction nanopillar with interfacial perpendicular magnetic anisotropy (PMA-MTJ) becomes a promising candidate to build up spin transfer torque magnetic random access memory (STT-MRAM) for the next generation of non-volatile memory as it features low spin transfer switching current, fast speed, high scalability, and easy integration into conventional complementary metal oxide semiconductor (CMOS) circuits. However, this device suffers from a number of failure issues, such as large process variation and tunneling barrier breakdown. The large process variation is an intrinsic issue for PMA-MTJ as it is based on the interfacial effects between ultra-thin films with few layers of atoms; the tunneling barrier breakdown is due to the requirement of an ultra-thin tunneling barrier (e.g., <1 nm) to reduce the resistance area for the spin transfer torque switching in the nanopillar. These failure issues limit the research and development of STT-MRAM to widely achieve commercial products. In this paper, we give a full analysis of failure mechanisms for PMA-MTJ and present some eventual solutions from device fabrication to system level integration to optimize the failure issues.

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Section: Failure Issues Due To Nanofabrication Of Magnetic Tunnel mentioning

confidence: 99%

Failure Analysis in Magnetic Tunnel Junction Nanopillar with Interfacial Perpendicular Magnetic Anisotropy

et al. 2016

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“…Magnetic tunnel junctions with perpendicular anisotropy (p-MTJs) are attracting attention as memory elements in nonvolatile large-scale integrated circuits (LSIs), 1) because it has good scalability, high-speed switching, and potential to realize zero standby power. Recently, p-MTJs have been miniaturized to 10 nm with high thermal tolerance, [2][3][4] and their application to high-density nonvolatile working memory such as spin-transfer torque magnetoresistive random access memory (STT-MRAM) with miniaturized p-MTJ cells has been reported. [5][6][7][8][9][10][11][12] However, there are several problems in increasing the density of LSIs.…”

Section: Introductionmentioning

confidence: 99%

Model of inter-cell interference phenomenon in 10 nm magnetic tunnel junction with perpendicular anisotropy array due to oscillatory stray field from neighboring cells

Ohuchida

Endoh

2018

Jpn. J. Appl. Phys.

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In this paper, we propose a new model of inter-cell interference phenomenon in a 10 nm magnetic tunnel junction with perpendicular anisotropy (p-MTJ) array and investigated the interference effect between a program cell and unselected cells due to the oscillatory stray field from neighboring cells by Landau-Lifshitz-Gilbert micromagnetic simulation. We found that interference brings about a switching delay in a program cell and excitation of magnetization precession in unselected cells even when no programing current passes through. The origin of interference is ferromagnetic resonance between neighboring cells. During the interference period, the precession frequency of the program cell is 20.8 GHz, which synchronizes with that of the theoretical precession frequency f = γH eff in unselected cells. The disturbance strength of unselected cells decreased to be inversely proportional to the cube of the distance from the program cell, which is in good agreement with the dependence of stray field on the distance from the program cell calculated by the dipole approximation method.

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“…Magnetic tunnel junctions with a perpendicular easy axis (p-MTJs) are promising building blocks to replace conventional volatile memories embedded in very-large-scale integrated circuits (VLSIs) for energy-saving computer systems. 1,2) A CoFeB=MgO=CoFeB p-MTJ exhibited a very large tunnel magnetoresistance (TMR) ratio, low switching current, high thermal stability factor, and good compatibility with backend-of-line Si CMOS processes, [3][4][5][6][7] showing potential to satisfy the requirements for implementation into VLSIs.…”

Section: Introductionmentioning

confidence: 99%

Study on initial current leakage spots in CoFeB-capped MgO tunnel barrier by conductive atomic force microscopy

Sato

Honjo

Ikeda

et al. 2016

Jpn. J. Appl. Phys.

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Although a microscopic study on a MgO tunnel barrier by atomic force microscopy has been required to study the reliability of magnetic tunnel junctions, the deterioration of bare MgO due to the adsorption of H2O and CO2 has been a problem. For an accurate evaluation of the initial current leakage spots distributed in a MgO tunnel barrier, a CoFeB-capped MgO tunnel barrier structure is proposed for evaluation by means of conductive atomic force microscopy. The CoFeB capping layer thickness was optimized to be 2.0 nm to prevent H2O and CO2 adsorption on the MgO and to minimize the series resistance due to the capping layer. The initial current leakage spot density of the MgO tunnel barrier with the optimized CoFeB capping layer exponentially increased as the thickness of the MgO tunnel barrier decreased from 1.6 to 0.8 nm, and was 157 spots/µm2 at the MgO thickness of 1.2 nm and the bias voltage of 0.5 V.

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10 nm\phi perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction with over 400°C high thermal tolerance by boron diffusion control

Cited by 24 publications

References 4 publications

Failure Analysis in Magnetic Tunnel Junction Nanopillar with Interfacial Perpendicular Magnetic Anisotropy

Failure Analysis in Magnetic Tunnel Junction Nanopillar with Interfacial Perpendicular Magnetic Anisotropy

Model of inter-cell interference phenomenon in 10 nm magnetic tunnel junction with perpendicular anisotropy array due to oscillatory stray field from neighboring cells

Study on initial current leakage spots in CoFeB-capped MgO tunnel barrier by conductive atomic force microscopy

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