Time Dependent Percolation Analysis of the Degradation of Coherent Tunneling in Ultra-Thin CoFeB/MgO/CoFeB Magnetic Tunneling Junctions

Keiji HOSOTANI; Makoto NAGAMINE; Ryu HASUNUMA

doi:10.1587/transele.2019ECP5014

Time Dependent Percolation Analysis of the Degradation of Coherent Tunneling in Ultra-Thin CoFeB/MgO/CoFeB Magnetic Tunneling Junctions

Keiji HOSOTANI, Makoto NAGAMINE, Ryu HASUNUMA

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We performed a time dependent percolation analysis of the degradation phenomena in ultra-thin CoFeB/MgO/CoFeB magnetic tunneling junctions. The objective was to understand the microscopic degradation physics of coherent tunneling and the thickness limitation of the MgO barrier. We propose two models: a trap assisted tunneling (TAL) model and a filamentary defect assisted leakage (FAL) model. The correlation between resistance drift behavior and barrier lifetime was then calculated and compared with real data based on these models. The relationship between the resistance drift behavior and barrier lifetime was found to be well explained by the TAL model, the random trap formation in the barrier and the percolation path formation which lead to barrier breakdown. Based on the TAL model, the measured TDDB Weibull slope (β) was smaller than the value estimated by the model. By removing the effect of some initial defects in the barrier, an ultra-thin MgO tunneling barrier in MTJ has the potential for a much better lifetime with a better Weibull slope even at 3ML thickness. This method is rather simple but useful to deeply understand the microscopic degradation physics in dielectric films under TDDB stress.

Publication: IEICE TRANSACTIONS on Electronics Vol.E103-C No.5 pp.254-262

Publication Date: 2020/05/01

Publicized: 2019/12/06

Online ISSN: 1745-1353

DOI: 10.1587/transele.2019ECP5014

Type of Manuscript: PAPER

Category: Semiconductor Materials and Devices

Authors

Keiji HOSOTANI
  Kioxia Corp.
Makoto NAGAMINE
  Kioxia Corp.
Ryu HASUNUMA
  University of Tsukuba

Keyword

STT-MRAM, MgO, TDDB, percolation

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Keiji HOSOTANI, Makoto NAGAMINE, Ryu HASUNUMA, "Time Dependent Percolation Analysis of the Degradation of Coherent Tunneling in Ultra-Thin CoFeB/MgO/CoFeB Magnetic Tunneling Junctions" in IEICE TRANSACTIONS on Electronics, vol. E103-C, no. 5, pp. 254-262, May 2020, doi: 10.1587/transele.2019ECP5014.
Abstract: We performed a time dependent percolation analysis of the degradation phenomena in ultra-thin CoFeB/MgO/CoFeB magnetic tunneling junctions. The objective was to understand the microscopic degradation physics of coherent tunneling and the thickness limitation of the MgO barrier. We propose two models: a trap assisted tunneling (TAL) model and a filamentary defect assisted leakage (FAL) model. The correlation between resistance drift behavior and barrier lifetime was then calculated and compared with real data based on these models. The relationship between the resistance drift behavior and barrier lifetime was found to be well explained by the TAL model, the random trap formation in the barrier and the percolation path formation which lead to barrier breakdown. Based on the TAL model, the measured TDDB Weibull slope (β) was smaller than the value estimated by the model. By removing the effect of some initial defects in the barrier, an ultra-thin MgO tunneling barrier in MTJ has the potential for a much better lifetime with a better Weibull slope even at 3ML thickness. This method is rather simple but useful to deeply understand the microscopic degradation physics in dielectric films under TDDB stress.
URL: https://global.ieice.org/en_transactions/electronics/10.1587/transele.2019ECP5014/_p

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@ARTICLE{e103-c_5_254,
author={Keiji HOSOTANI, Makoto NAGAMINE, Ryu HASUNUMA, },
journal={IEICE TRANSACTIONS on Electronics},
title={Time Dependent Percolation Analysis of the Degradation of Coherent Tunneling in Ultra-Thin CoFeB/MgO/CoFeB Magnetic Tunneling Junctions},
year={2020},
volume={E103-C},
number={5},
pages={254-262},
abstract={We performed a time dependent percolation analysis of the degradation phenomena in ultra-thin CoFeB/MgO/CoFeB magnetic tunneling junctions. The objective was to understand the microscopic degradation physics of coherent tunneling and the thickness limitation of the MgO barrier. We propose two models: a trap assisted tunneling (TAL) model and a filamentary defect assisted leakage (FAL) model. The correlation between resistance drift behavior and barrier lifetime was then calculated and compared with real data based on these models. The relationship between the resistance drift behavior and barrier lifetime was found to be well explained by the TAL model, the random trap formation in the barrier and the percolation path formation which lead to barrier breakdown. Based on the TAL model, the measured TDDB Weibull slope (β) was smaller than the value estimated by the model. By removing the effect of some initial defects in the barrier, an ultra-thin MgO tunneling barrier in MTJ has the potential for a much better lifetime with a better Weibull slope even at 3ML thickness. This method is rather simple but useful to deeply understand the microscopic degradation physics in dielectric films under TDDB stress.},
keywords={},
doi={10.1587/transele.2019ECP5014},
ISSN={1745-1353},
month={May},}

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TY - JOUR
TI - Time Dependent Percolation Analysis of the Degradation of Coherent Tunneling in Ultra-Thin CoFeB/MgO/CoFeB Magnetic Tunneling Junctions
T2 - IEICE TRANSACTIONS on Electronics
SP - 254
EP - 262
AU - Keiji HOSOTANI
AU - Makoto NAGAMINE
AU - Ryu HASUNUMA
PY - 2020
DO - 10.1587/transele.2019ECP5014
JO - IEICE TRANSACTIONS on Electronics
SN - 1745-1353
VL - E103-C
IS - 5
JA - IEICE TRANSACTIONS on Electronics
Y1 - May 2020
AB - We performed a time dependent percolation analysis of the degradation phenomena in ultra-thin CoFeB/MgO/CoFeB magnetic tunneling junctions. The objective was to understand the microscopic degradation physics of coherent tunneling and the thickness limitation of the MgO barrier. We propose two models: a trap assisted tunneling (TAL) model and a filamentary defect assisted leakage (FAL) model. The correlation between resistance drift behavior and barrier lifetime was then calculated and compared with real data based on these models. The relationship between the resistance drift behavior and barrier lifetime was found to be well explained by the TAL model, the random trap formation in the barrier and the percolation path formation which lead to barrier breakdown. Based on the TAL model, the measured TDDB Weibull slope (β) was smaller than the value estimated by the model. By removing the effect of some initial defects in the barrier, an ultra-thin MgO tunneling barrier in MTJ has the potential for a much better lifetime with a better Weibull slope even at 3ML thickness. This method is rather simple but useful to deeply understand the microscopic degradation physics in dielectric films under TDDB stress.
ER -