Dual-Port SOT-MRAM Achieving 90-MHz Read and 60-MHz Write Operations under Field-Assistance-Free Condition

Masanori Natsui, Akira Tamakoshi, Hiroaki Honjo, Toshinari Watanabe, Takashi Nasuno, Chaoliang Zhang, Takaho Tanigawa, Hirofumi Inoue, Masaaki Niwa, Toru Yoshiduka, Yasuo Noguchi, Mitsuo Yasuhira, Yitao Ma, Hui Shen, Shunsuke Fukami, Hideo Sato, Shoji Ikeda, Hideo Ohno, Tetsuo Endoh, Takahiro Hanyu

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


The development of new functional memories using emerging nonvolatile devices has been widely investigated. Spin-transfer torque magnetoresistive random access memory (STT-MRAM) has become new technology platform to overcome the issue in power consumption of logic for the application from IoT to AI; however, STT-MRAM has a tradeoff relationship between endurance, retention, and access time. This is because the MTJ device used in STT-MRAM is a two-terminal device, and excessive read current for high-speed readout can cause unexpected data writing, or so-called read disturbance. In order to meet the demand for the realization of high-speed nonvolatile memory, the development of new memories based on innovative circuit, device, and integration process is required. In this article, we demonstrate an SOT-MRAM, a nonvolatile memory using MTJ devices with spin-orbit-torque (SOT) switching that have a read-disturbance-free characteristic. The SOT-MRAM fabricated using a 55-nm CMOS process is implemented in a dual-port configuration utilizing a three-terminal structure of the device for realizing a wide bandwidth applicable to high-speed applications. In addition, a read-energy reduction technique called a self-termination scheme is also implemented. Through the measurement results of the fabricated prototype chip, we will demonstrate the proposed SOT-MRAM achieves 60-MHz write and 90-MHz read operations with 1.2-V supply voltage under a magnetic-field-free condition.

Original languageEnglish
Article number9288784
Pages (from-to)1116-1128
Number of pages13
JournalIEEE Journal of Solid-State Circuits
Issue number4
Publication statusPublished - 2021 Apr


  • Dual-port
  • Magnetic tunnel junction
  • Spin-orbit-torque (SOT)
  • Spintronics
  • magnetoresistive random access memory (MRAM)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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