Scalability of Quad Interface p-MTJ for 1X nm STT-MRAM with 10-ns Low Power Write Operation, 10 Years Retention and Endurance > 10¹¹

Sadahiko Miura, Koichi Nishioka, Hiroshi Naganuma, T. V.A. Nguyen, Hiroaki Honjo, Shoji Ikeda, Toshinari Watanabe, Hirofumi Inoue, Masaaki Niwa, Takaho Tanigawa, Yasuo Noguchi, Toru Yoshizuka, Mitsuo Yasuhira, Tetsuo Endoh

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


We fabricated a quadruple-interface perpendicular magnetic tunnel junction (MTJ) (Quad-MTJ) down to 33 nm using physical vapor-deposition, reactive ion etching, and damage-control integration process technologies that we developed under a 300-mm process. We demonstrated the greater scalability and higher writing speed of Quad-MTJ compared with double-interface perpendicular MTJ: 1) it has twice the thermal stability factor - 1X nm Quad-MTJ can achieve 10 years retention - while maintaining a low resistance-area product and high tunnel magnetoresistance ratio; 2) smaller overdrive ratio of write voltage to obtain a sufficiently low write-error rate; 2) smaller pulsewidth dependence of the switching current; and 4) more than double the write efficiency at 10-ns write operation down to 33-nm MTJ. The effective suppression of the switching current increase for higher write speeds was explained by the spin-transfer-torque model using the Fokker-Planck equation. Our 33-nm Quad-MTJ also achieved excellent endurance (at least 1011) owing to its higher write efficiency and low-damage integration-process technology. It is thus a promising method for low power, high speed, and reliable STT-MRAM with excellent scalability down to the 1X nm node.

Original languageEnglish
Article number9212560
Pages (from-to)5368-5373
Number of pages6
JournalIEEE Transactions on Electron Devices
Issue number12
Publication statusPublished - 2020 Dec


  • Interfacial-perpendicular magnetic anisotropy (i-PMA)
  • p-magnetic tunnel junction (MTJ) (p-MTG)
  • quad interface
  • scalability
  • spin-transfer-torque magnetoresistive random access memory (STT-MRAM)
  • thermal stability factor
  • write efficiency

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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