A scaling roadmap and performance evaluation of in-plane and perpendicular MTJ based STT-MRAMs for high-density cache memory

Ki Chul Chun, Hui Zhao, Jonathan D. Harms, Tae Hyoung Kim, Jianping Wang, Chris H. Kim

Research output: Contribution to journalArticlepeer-review

314 Scopus citations

Abstract

This paper explores the scalability of in-plane and perpendicular MTJ based STT-MRAMs from 65 nm to 8 nm while taking into consideration realistic variability effects. We focus on the read and write performances of a STT-MRAM based cache rather than the obvious advantages such as the denser bit-cell and zero static power. An accurate MTJ macromodel capturing key MTJ properties was adopted for efficient Monte Carlo simulations. For the simulation of access devices and peripheral circuitries, ITRS projected transistor parameters were utilized and calibrated using the MASTAR tool that has been widely used in industry. 6T SRAM and STT-MRAM arrays were implemented with aggressive assist schemes to mimic industrial memory designs. A constant JC0 RA/VDD scaling scenario was used which to the first order gives the optimal balance between read and write margins of STT-MRAMs. The thermal stability factor ensuring a 10 year retention time was obtained by adjusting the free layer thickness as well as assuming improvement in the crystalline anisotropy. Our studies based on the proposed scaling methodology show that in-plane STT-MRAM will outperform SRAM from 15 nm node, while its perpendicular counterpart requires further innovations in MTJ material in order to overcome the poor write performance scaling from 22 nm node onwards.

Original languageEnglish (US)
Article number6374706
Pages (from-to)598-610
Number of pages13
JournalIEEE Journal of Solid-State Circuits
Volume48
Issue number2
DOIs
StatePublished - 2013

Keywords

  • Cache
  • STT-MRAM
  • macromodel
  • magnetic tunnel junction (MTJ)
  • roadmap
  • scalability
  • spin torque transfer (STT)
  • variability

Fingerprint

Dive into the research topics of 'A scaling roadmap and performance evaluation of in-plane and perpendicular MTJ based STT-MRAMs for high-density cache memory'. Together they form a unique fingerprint.

Cite this