Complex capacitance spectroscopy as a probe for oxidation process of AlOx -based magnetic tunnel junctions

J. C.A. Huang, C. Y. Hsu

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15 Citations (Scopus)


Proper as well as under- and over-oxided CoFe- AlOx -CoFe magnetic tunnel junctions (MTJs) have been systematically investigated in a frequency range from 102 to 108 Hz by complex capacitance spectroscopy. The dielectric relaxation behavior of the MTJs remarkably disobeys the typical Cole-Cole arc law probably due to the existence of imperfectly blocked Schottky barrier in the metal-insulator interface. The dielectric relaxation response can be successfully modeled on the basis of Debye relaxation by incorporating an interfacial dielectric contribution. In addition, complex capacitance spectroscopy demonstrates significant sensitivity to the oxidation process of metallic Al layers, i.e., almost a fingerprint of under, proper, and over oxidation. This technique provides a fast and simple method to inspect the AlOx barrier quality of MTJs.

Original languageEnglish
Pages (from-to)5947-5949
Number of pages3
JournalApplied Physics Letters
Issue number24
Publication statusPublished - 2004 Dec 13

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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