Precise Damage Observation in Ion-Beam Etched MTJ

Ohsawa, Yoshiaki; Shimomura, N.; Daibou, T.; Kamiguchi, Y.; Shirotori, S.; Inokuchi, T.; Saida, Daisuke; Altansargai, B.; Kato, Y.; Yasuda, Hiroaki; Ohkubo, T.; Hara, Kazuhiro

doi:10.1109/tmag.2015.2512588

Cited by 16 publications

(3 citation statements)

References 6 publications

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“…Pitch scaling also tends to increase the failure rate by forming shunting paths on the sidewall due to metallic re-deposition during MTJ patterning. 36 The physical and chemical damages on the pillar sidewall become even more problematic for downscaled MTJ devices.…”

Section: Commercialization and Challenges Of Spin Memorymentioning

confidence: 99%

Two-dimensional materials prospects for non-volatile spintronic memories

Yang

Valenzuela

Chshiev

et al. 2022

Nature

182

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Non-volatile magnetic random access memories such as spin-transfer torque (STT)-MRAM and next generation spin-orbit torque (SOT)-MRAM are emerging as key enabling low-power technologies, which are expected to spread over large markets from embedded memories to the Internet of Things. Concurrently, the development and performances of devices based on two-dimensional (2D) van der Waals heterostructures bring ultra-compact multilayer compounds with unprecedented material-engineering capabilities. Here, we first provide an overview of the current developments and challenges in the field, and then outline the opportunities which can arise by implementing 2D materials into spin-based memory technologies. We highlight the fundamental properties of atomically smooth interfaces, the reduced material intermixing, the crystal symmetries and the proximity effects as the key drivers for possible disruptive improvements for MRAM at advanced technology nodes.

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Section: Commercialization and Challenges Of Spin Memorymentioning

confidence: 99%

Two-dimensional materials prospects for non-volatile spintronic memories

Yang

Valenzuela

Chshiev

et al. 2022

Nature

182

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“…However, the dry etching of MTJ stack with sub 70 nm is a challenging step in the fabrication of STT-MRAM [8]. The etching of nanoscale MTJ induces oxidation in magnetic layer, pattern degradation and damage, or sidewall redeposition with the slanted etch slope of the patterned MTJ sidewall [9]. The etch process using C-O based chemistry and halogen gas induces more magnetic degradation in magnetic tunneling junctions (MTJs) compare to Ar.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Spin-Transfer Torque MRAM Etching Using Various Gases

et al. 2017

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“…[5][6][7][8][9][10][11] Ar ion milling (or Ar ion beam etch (IBE)) has been used to etch MTJ materials. [12][13][14] The advantage of the Ar ion milling is that the process induces very little or no chemical damage to the MTJ materials. To improve the etch profile and to remove the sidewall redeposition, a side-milling process (etching by tilting) has been applied.…”

mentioning

confidence: 99%

Improved Etch Characteristics of Magnetic Tunneling Junction Materials by Using Helium

Park

Yang

Lee

et al. 2017

ECS J. Solid State Sci. Technol.

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The etch characteristics of magnetic tunneling junction (MTJ) materials for spin transfer torque magnetic random access memory (STT-MRAM) using He inductively coupled plasma (ICP) were compared with the etch characteristics of ICP using Ar or CO/NH 3 (1:3). The ICP etching using He showed a higher etch selectivity of CoFeB over W and a more anisotropic etch profile compared to the etching using Ar at similar etch rates. The sputter etch characteristics of CoFeB and W were also investigated using the Stopping and Range of Ions in Matter (SRIM) simulation program. The results showed higher sputter etch selectivity of CoFeB over W in addition to narrower angular distribution of the sputtered atoms than those obtained using Ar. The etching of MTJ materials using CO/NH 3 (1:3) ICP exhibited good MTJ etch characteristics comparable to He ICP, however, the MTJ etched using CO/NH 3 (1:3) showed the lowest saturation magnetization (M S) measured by a vibrating-sample magnetometer (VSM) possibly due to the sidewall oxidation of MTJ while the M S values of the MTJ etched using He and Ar are similar. It is found that, by etching the MTJ materials using He ICP with the ion energy near the hardmask sputter threshold energy, highly anisotropic etch profiles could be obtained without forming the sidewall redeposited materials and without significant degradation of magnetic properties.

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Precise Damage Observation in Ion-Beam Etched MTJ

Cited by 16 publications

References 6 publications

Two-dimensional materials prospects for non-volatile spintronic memories

Two-dimensional materials prospects for non-volatile spintronic memories

Nanoscale Spin-Transfer Torque MRAM Etching Using Various Gases

Improved Etch Characteristics of Magnetic Tunneling Junction Materials by Using Helium

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