Ion beam deposition and oxidation of spin-dependent tunnel junctions

Author

Cardoso, Susana ; Gehanno, Véronique ; Ferreira, Ricardo ; Freitas, Paulo P.

Author_Institution

INESC, Lisbon, Portugal

Volume

35

Issue

5

fYear

1999

fDate

9/1/1999 12:00:00 AM

Firstpage

2952

Lastpage

2954

Abstract

Spin dependent tunnel junctions showing tunnel magnetoresistance (TMR) values of 39~41% were fabricated using Ion Beam Deposition (IBD). Both the electrodes and the aluminum layer deposition were done by IBD. The aluminum oxidation was performed using the assist gun with an oxygen beam (+30 V acceleration voltage applied on the grids) using mixed O₂/Ar plasma. The oxidation was monitored in real time with a residual gas analyzer (RGA). The junction area is defined by lithography, down to 3×2 μm². As-deposited junctions with 15 Å of Al showed TMR of 27~29%, independent of the junction area, with resistance-area products of 0.8~1.6 MΩ×μm². This TMR value reached 40% upon annealing at 290°C, with resistance decreasing to 0.5~0.8 MΩ×μm²

Keywords

alumina; aluminium; annealing; giant magnetoresistance; interface magnetism; ion beam assisted deposition; oxidation; plasma materials processing; tunnelling; vacuum deposition; 15 A; 2 mum; 290 C; 3 mum; Al; Al₂O₃; Ar; O₂; aluminum layer deposition; annealing; electrodes; ion beam deposition; lithography; mixed O₂/Ar plasma; oxidation; residual gas analysis; resistance-area products; spin-dependent tunnel junctions; tunnel magnetoresistance; Acceleration; Aluminum; Argon; Electrodes; Ion beams; Oxidation; Particle beams; Plasma accelerators; Tunneling magnetoresistance; Voltage;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.801044

Filename

801044