Magnetic properties and writing characteristics of magnetic clad lines in magnetoresistive random access memory devices

Norikazu Ohshima, Ken ichi Shimura, Sadahiko Miura, Tetsuhiro Suzuki, Ryusuke Nebashi, Hiromitsu Hada

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Structural and magnetic properties of magnetic clad lines used for magnetoresistive random access memory (MRAM) devices were analyzed to optimize the clad-line fabrication process. Patterns of 520 nm lines and 280 nm spaces with a depth of 300 nm with magnetic cladding films of Ta/NiFe/Ta were fabricated to characterize the structure and magnetic properties of cladding films by transmission electron microscopy and magnetic measurements. A high susceptibility with a small hysteresis was obtained when a NiFe cladding film highly oriented to fee (111) was formed perpendicular to the sidewall depth direction, The optimized cladding film was integrated in MRAM cells and we confirmed that the clad lines reduced the flop current of a toggle-MRAM cell by more than 50% compared with a cell having unclad lines. The flop current distribution can be reduced by applying a magnetic field of 12 kOe in the direction of word lines at room temperature. We successfully confirmed writing operation in a 4-Mbit MRAM cell with these optimized magnetic clad lines.

Original languageEnglish
Pages (from-to)3456-3460
Number of pages5
JournalJapanese journal of applied physics
Volume47
Issue number5 PART 1
DOIs
Publication statusPublished - 2008 May 16
Externally publishedYes

Keywords

  • Clad line
  • Magnetic properties
  • Structure
  • Toggle magnetoresistive random access memory (MRAM)
  • Writing current

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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