Sophisticated process for a spin-torque device fabricated from a pillar containing two different ferromagnetic materials separated by a non-magnetic layer

• Published in: Microelectronic engineering Vol. 119; pp. 20 - 23
• Main Authors: Samiepour, M., Gerhard, F., Borzenko, T., Gould, C., Molenkamp, L.W.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2014
• Subjects: Cross-linked PMMA; Devices; Electron beam lithography; Ferromagnetic materials; Ferromagnetism; Ion beam etching; Magnetic fields; Pillars; Poly(methyl methacrylate) (PMMA); Reactive ion etching; Spacers; Spin torque devices; Switching; Walls; Ion beam etching; Reactive ion etching; Poly(methyl methacrylate) (PMMA); Cross-linked PMMA; Electron beam lithography; Spin torque devices
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2014.01.013

[Display omitted] •Flaws in conventional magnetic junction nanopillar fabrication processes are examined.•Cross-linked PMMA is used for pillar protection against lateral surface conductivity.•Yield of structures showing functional spin valve characteristic is increased. Since several years, devices allowing for spin manipulation in ferromagnetic layers are the subject of intensive research (e.g., Ralph and Stiles (2008) [1]). A pillar with sub-micrometer dimensions fabricated from a stack of various materials containing two or more ferromagnetic layers separated with a spacer very often serves as a core of devices suitable for investigation of spin torque phenomena. Here we describe a reliable fabrication process for such pillars emphasizing precautions which have to be taken to protect pillar side walls from surface conductivity thereby increasing the percentage of the structures revealing magnetic field/current induced switching events.