Predictive Materials Design of Magnetic Random-Access Memory Based on Nanoscale Atomic Structure and Element Distribution

Li, Xiang; Sasaki, Taisuke; Grezes, Cecile; Wu, Di; Wong, Kin L.; Bi, Chong; Ong, Phuong-Vu; Ebrahimi, Farbod; Yu, Guoqiang; Kioussis, Nicholas; Wang, Weigang; Ohkubo, Tadakatsu; Khalili Amiri, Pedram; Wang, Kang L.

doi:10.1021/acs.nanolett.9b03190

Title: Predictive Materials Design of Magnetic Random-Access Memory Based on Nanoscale Atomic Structure and Element Distribution

Full Record
Other Related Research

Abstract

Magnetic tunnel junctions (MTJs) capable of electrical read and write operations have emerged as a canonical building block for non-volatile memory and logic. However, the cause of the wide-spread device properties found experimentally in various MTJ stacks, including tunneling magnetoresistance (TMR), perpendicular magnetic anisotropy (PMA), and voltage-controlled magnetic anisotropy (VCMA), remains elusive. Here, using high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy, we found that the MTJ crystallization quality, boron diffusion out of the CoFeB fixed layer, and minimal CoFe oxidation correlate with the TMR. As with the CoFeB free layer, seed layer diffusion into the free layer/MgO interface is negatively correlated with the interfacial PMA, while the metal-oxides concentrations in the free layer correlate with the VCMA. Combined with formation enthalpy and thermal diffusion analysis, we further established a predictive materials design framework to guide the complex design space explorations for high-performance MTJs. In this paper, we demonstrate experimentally high PMA and VCMA values of 1.74 mJ/m2 and 115 fJ/V-m with annealing stability above 400 °C.

Authors:

Li, Xiang ^[1]; Sasaki, Taisuke ^[2]; Grezes, Cecile ^[3]; Wu, Di ^[3]; Wong, Kin L. ^[3]; Bi, Chong ^[4]; Ong, Phuong-Vu ^[5]; Ebrahimi, Farbod ^[6]; Yu, Guoqiang ^[3]; Kioussis, Nicholas ^[5]; Wang, Weigang ^[4]; Ohkubo, Tadakatsu ^[2]; Khalili Amiri, Pedram ^[7]; Wang, Kang L. ^[3]

Univ. of California, Los Angeles, CA (United States). Dept. of Electrical and Computer Engineering; Inston, Inc., Los Angeles, CA (United States); Stanford Univ., CA (United States). Dept. of Electrical Engineering
National Inst. for Materials Science (NIMS), Tsukuba (Japan)
Univ. of California, Los Angeles, CA (United States). Dept. of Electrical and Computer Engineering
Univ. of Arizona, Tucson, AZ (United States). Dept. of Physics
California State Univ. Northridge, CA (United States).Dept. of Physics and Astronomy
Inston, Inc., Los Angeles, CA (United States); Happy Electron Lab Inc., Redwood City, CA (United States)
Univ. of California, Los Angeles, CA (United States). Dept. of Electrical and Computer Engineering; Northwestern Univ., Evanston, IL (United States). Dept. of Electrical Engineering and Computer Science

Publication Date:: Thu Nov 07 00:00:00 EST 2019

Research Org.:: Univ. of California, Riverside, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:: 1573371

Grant/Contract Number:: SC0012670

Resource Type:: Accepted Manuscript

Journal Name:: Nano Letters

Additional Journal Information:: Journal Volume: 19; Journal Issue: 12; Journal ID: ISSN 1530-6984

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; voltage-controlled magnetic anisotropy; perpendicular magnetic anisotropy; tunneling magnetoresistance; crystal structure; element distribution; magnetic tunnel junction

Citation Formats


                    Li, Xiang, Sasaki, Taisuke, Grezes, Cecile, Wu, Di, Wong, Kin L., Bi, Chong, Ong, Phuong-Vu, Ebrahimi, Farbod, Yu, Guoqiang, Kioussis, Nicholas, Wang, Weigang, Ohkubo, Tadakatsu, Khalili Amiri, Pedram, and Wang, Kang L. Predictive Materials Design of Magnetic Random-Access Memory Based on Nanoscale Atomic Structure and Element Distribution.  United States: N. p., 2019. 
Web.  doi:10.1021/acs.nanolett.9b03190.

Copy to clipboard


                    Li, Xiang, Sasaki, Taisuke, Grezes, Cecile, Wu, Di, Wong, Kin L., Bi, Chong, Ong, Phuong-Vu, Ebrahimi, Farbod, Yu, Guoqiang, Kioussis, Nicholas, Wang, Weigang, Ohkubo, Tadakatsu, Khalili Amiri, Pedram, & Wang, Kang L. Predictive Materials Design of Magnetic Random-Access Memory Based on Nanoscale Atomic Structure and Element Distribution.  United States.  https://doi.org/10.1021/acs.nanolett.9b03190

Copy to clipboard


                    Li, Xiang, Sasaki, Taisuke, Grezes, Cecile, Wu, Di, Wong, Kin L., Bi, Chong, Ong, Phuong-Vu, Ebrahimi, Farbod, Yu, Guoqiang, Kioussis, Nicholas, Wang, Weigang, Ohkubo, Tadakatsu, Khalili Amiri, Pedram, and Wang, Kang L. Thu .  
"Predictive Materials Design of Magnetic Random-Access Memory Based on Nanoscale Atomic Structure and Element Distribution".  United States.  https://doi.org/10.1021/acs.nanolett.9b03190.  https://www.osti.gov/servlets/purl/1573371.

Copy to clipboard


                    
@article{osti_1573371,

  title        = {Predictive Materials Design of Magnetic Random-Access Memory Based on Nanoscale Atomic Structure and Element Distribution},

  author       = {Li, Xiang and Sasaki, Taisuke and Grezes, Cecile and Wu, Di and Wong, Kin L. and Bi, Chong and Ong, Phuong-Vu and Ebrahimi, Farbod and Yu, Guoqiang and Kioussis, Nicholas and Wang, Weigang and Ohkubo, Tadakatsu and Khalili Amiri, Pedram and Wang, Kang L.},

  abstractNote = {Magnetic tunnel junctions (MTJs) capable of electrical read and write operations have emerged as a canonical building block for non-volatile memory and logic. However, the cause of the wide-spread device properties found experimentally in various MTJ stacks, including tunneling magnetoresistance (TMR), perpendicular magnetic anisotropy (PMA), and voltage-controlled magnetic anisotropy (VCMA), remains elusive. Here, using high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy, we found that the MTJ crystallization quality, boron diffusion out of the CoFeB fixed layer, and minimal CoFe oxidation correlate with the TMR. As with the CoFeB free layer, seed layer diffusion into the free layer/MgO interface is negatively correlated with the interfacial PMA, while the metal-oxides concentrations in the free layer correlate with the VCMA. Combined with formation enthalpy and thermal diffusion analysis, we further established a predictive materials design framework to guide the complex design space explorations for high-performance MTJs. In this paper, we demonstrate experimentally high PMA and VCMA values of 1.74 mJ/m2 and 115 fJ/V-m with annealing stability above 400 °C.},

  doi          = {10.1021/acs.nanolett.9b03190},

  journal      = {Nano Letters},

  number       = 12,

  volume       = 19,

  place        = {United States},

  year         = {Thu Nov 07 00:00:00 EST 2019},

  month        = {Thu Nov 07 00:00:00 EST 2019}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1021/acs.nanolett.9b03190

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 16 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

Enhancement of voltage-controlled magnetic anisotropy through precise control of Mg insertion thickness at CoFeB|MgO interface

Journal Article Li, Xiang ; Fitzell, Kevin ; Wu, Di ; ... - Applied Physics Letters

We studied the impact of different insertion layers (Ta, Pt, and Mg) at the CoFeB|MgO interface on voltage-controlled magnetic anisotropy (VCMA) effect and other magnetic properties. Inserting a very thin Mg layer of 0.1–0.3 nm yielded a VCMA coefficient of 100 fJ/V-m, more than 3 times higher than the average values of around 30 fJ/V-m reported in Ta|CoFeB|MgO-based structures. Ta and Pt insertion layers also showed a small improvement, yielding VCMA coefficients around 40 fJ/V-m. Electrical, magnetic, and X-ray diffraction results reveal that a Mg insertion layer of around 1.2 nm gives rise to the highest perpendicular magnetic anisotropy, saturationmore »« less
Cited by 81
https://doi.org/10.1063/1.4975160

Full Text Available
Thin Co/Ni-based bottom pinned spin-transfer torque magnetic random access memory stacks with high annealing tolerance

Journal Article Tomczak, Y., E-mail: Yoann.Tomczak@imec.be ; Department of Chemistry, KU Leuven ; Swerts, J. ; ... - Applied Physics Letters

Spin-transfer torque magnetic random access memory (STT-MRAM) is considered as a replacement for next generation embedded and stand-alone memory applications. One of the main challenges in the STT-MRAM stack development is the compatibility of the stack with CMOS process flows in which thermal budgets up to 400 °C are applied. In this letter, we report on a perpendicularly magnetized MgO-based tunnel junction (p-MTJ) on a thin Co/Ni perpendicular synthetic antiferromagnetic layer with high annealing tolerance. Tunnel magneto resistance (TMR) loss after annealing occurs when the reference layer loses its perpendicular magnetic anisotropy due to reduction of the CoFeB/MgO interfacial anisotropy. Amore »« less
https://doi.org/10.1063/1.4940772
Magnetic Characterization of CoFeB/MgO and CoFe/MgO Interfaces

Journal Article Negusse, E ; Lussier, A ; Dvorak, J ; ... - Applied Physics Letters

The use of CoFeB ferromagnetic electrodes in place of CoFe has been shown to significantly increase the tunneling magnetoresistance (TMR) of MgO based magnetic tunnel junctions (MTJs). By using soft x-ray scattering techniques, we show that the behavior of the magnetic moments located at the CoFe-MgO interface are drastically different from the rest of the CoFe film, whereas the magnetic response of the CoFeB-MgO interfacial moments is coherent with the film's bulk. Our results support the view that the high TMR values observed in MgO based MTJs with CoFeB electrodes are due to the uniform magnetic response of the entiremore »« less
https://doi.org/10.1063/1.2709619
Thermally stable voltage-controlled perpendicular magnetic anisotropy in Mo|CoFeB|MgO structures

Journal Article Li, Xiang ; Yu, Guoqiang ; Wong, Kin ; ... - Applied Physics Letters

We study voltage-controlled magnetic anisotropy (VCMA) and other magnetic properties in annealed Mo|CoFeB|MgO 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 studiedmore »« less
https://doi.org/10.1063/1.4932553
Atomic-scale spectroscopic imaging of CoFeB/Mg-B-O/CoFeB magnetic tunnel junctions

Journal Article Cha, J J ; Huang, P Y ; Tseng, H W ; ... - Applied Physics Letters

Atomic-scale electron spectroscopic imaging on sputtered magnetic tunnel junctions (MTJs) with a thin, <2 nm, MgO layer and B-alloyed electrodes reveals B diffusion into the MgO, resulting in a Mg-B-O tunnel barrier. This {approx}2 nm thick interfacial layer forms due to oxidation of CoFeB during radio frequency sputtering of MgO and subsequent B diffusion into MgO during annealing. We measure a room-temperature tunneling magnetoresistance (TMR) of {approx}200% in IrMn/CoFeB/Mg-B-O/CoFeB MTJs after annealing, demonstrating that thin Mg-B-O barriers can produce relatively high TMR.
https://doi.org/10.1063/1.3184766

Similar Records