Stray field and combined effects on device miniaturization of the magnetic tunnel junctions
Journal
Journal of Physics D: Applied Physics
Journal Volume
55
Journal Issue
19
Date Issued
2022
Author(s)
Abstract
Magneto-static stray field (H stray) interactions become an important issue when perpendicular CoFeB/MgO magnetic tunnel junctions (MTJs) are miniaturized. This raises the issue of which of the two mainstream etching processes, the pillar structure and the step structure, is better able to retain MTJ performance at extremely small scales. In the current study, we first simulated H stray effects as a function of Ruderman-Kittel-Kasuya-Yosida strength within a synthetic antiferromagnetic structure for the two structures. Our results revealed that H stray interactions were less influential (in terms of offset field) in step MTJs than in pillar MTJs during MTJ miniaturization. This is in good agreement with experimental results. This finding is further supported by adding Dzyaloshinskii-Moriya interactions into the free-layer of the two structures. We further simulated thermal stability with the inclusion of H stray for 30 nm MTJs. We found that adding etching damage effects (i.e. assuming both anisotropy constant and saturation magnetization of the free layer had some degree of loss) into the model of the pillar MTJ was necessary to obtain a trend that is close to the experimental results of thermal stability. This information can provide some guidance on the technical choices for the MTJ miniaturization. © 2022 IOP Publishing Ltd.
Subjects
Dzyaloshinskii-Moriya interactions; magnetic tunnel junction; micromagnetic simulation; sidewall etching damage; spin-transfer torque; stray field
Other Subjects
Etching; Magnetic devices; Miniature instruments; Saturation magnetization; Thermodynamic stability; Tunnel junctions; Dzyaloshinskii-Moriya interaction; Etching damages; Field-effect; Free layers; Magnetic tunnel junction; Micromagnetic simulations; Miniaturisation; Sidewall etching damage; Spin transfer torque; Stray field; Cobalt compounds
Type
journal article