Characterization of nano-oxide layers fabricated by ion beam oxidation

Author

Cardoso, Susana ; Zhang, Zongzhi ; Li, Haohua ; Ferreira, Ricardo ; Freitas, Paulo P. ; Wei, Peng ; Soares, José C. ; Snoeck, Etienne ; Batlle, Xavier

Author_Institution

Instituto Superior Tecnico, Lisbon, Portugal

Volume

38

Issue

5

fYear

2002

fDate

9/1/2002 12:00:00 AM

Firstpage

2755

Lastpage

2757

Abstract

In this paper, a remote O₂ ion source is used for the formation of nano-oxide layers. The oxidation efficiency was measured in CoFe-oxide films, and a decrease of the oxide layer with the pan angle and the oxidation pressure is observed. For the same oxidation pressure, the oxidation efficiency depends on the O₂ content in the Ar-O₂ plasma. These results were applied in optimizing the fabrication of Al₂O₃ barrier for tunnel junctions. This method was also used to fabricate junctions with Fe-oxide layers inserted at the Al₂O₃-CoFe interface. TEM and magnetization data indicate that after anneal at 385°C, a homogeneous ferromagnetic Fe-oxide layer (Fe₃O₄?) is formed.

Keywords

alumina; annealing; cobalt alloys; interface magnetism; ion beam effects; iron alloys; magnetisation; oxidation; plasma materials processing; transmission electron microscopy; tunnelling; 385 degC; Al₂O₃ barrier; Al₂O₃-CoFe; Al₂O₃-CoFe interface; Ar-O₂ plasma; CoFe-oxide film; Fe-oxide layer; Fe₃O₄; TEM; annealing; fabrication process; ion beam oxidation; magnetic tunnel junction; magnetization; nano-oxide layer; oxidation efficiency; oxidation pressure; pan angle; remote O₂ ion source; Annealing; Argon; Fabrication; Ion beams; Oxidation; Plasma accelerators; Plasma applications; Plasma sources; Spin valves; Tunneling magnetoresistance;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2002.802863

Filename

1042344