Effect of diffused b during annealing on the electronic structure of the MgO barrier in CoFeB/MgO/CoFeB magnetic tunnel junctions

Yoonsung Han, Jinhee Han, Hyoung Joon Choi, Hyun Joon Shin, Jongill Hong

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We investigate the chemical state and electronic structure of boron in the MgO layer in CoFeB/MgO/CoFeB magnetic tunnel junctions by synchrotron radiation X-ray photoelectron spectroscopy and first-principles calculations. In the top CoFeB, we observe three boron 1s peaks corresponding to oxidic, intermediate, and metallic boron. As the annealed films were etched, the B 2O 3 starts to appear together with the Mg 2p peak, indicating that boron atoms diffuse into the MgO barrier. Our calculations show that B impurities in the MgO barrier do not create any midgap states but reduce the MgO barrier height with the increase of boron concentration.

Original languageEnglish
Article number033001
JournalApplied Physics Express
Volume5
Issue number3
DOIs
Publication statusPublished - 2012 Mar 1

All Science Journal Classification (ASJC) codes

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

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