Magnetic tunnel junctions with doubly-plasma oxidized AlOx insulation layer

Y. M. Lee, O. Song, C. S. Yoon, C. K. Kim, Y. Ando, H. Kubota, T. Miyazaki

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Magnetic tunnel junctions (MTJ), with the tunnel barrier plasma oxidized in two steps, were fabricated in order to obtain structurally uniform AlOx insulator. The doubly oxidized junctions exhibited the magnetoresistance (MR) ratio of 27-31% without showing any noticeable drop in the MR ratio even after oxidation time was extended well beyond the optimal oxidation time for the normal junctions. Transmission electron microscopy of the junctions confirmed that the AlOx thickness was thinner for the doubly oxidized junctions compared to the singly oxidized MTJ. X-ray photoelectron spectroscopy of the doubly oxidized junction also strongly suggested that the initial oxide layer prevents the over-oxidation of the bottom electrode. The AlOx tunnel barrier oxidized in two steps improved the junction performance and widened the processing window.

Original languageEnglish
Pages (from-to)805-808
Number of pages4
JournalMicroelectronics Journal
Issue number9
StatePublished - Sep 2003


  • A1Ox tunnel barrier
  • Doubly oxidation
  • Inductively coupled plasma
  • Magnetic tunnel junction
  • Magnetoresistance ratio
  • Plasma oxidation


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