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Microstructural observation on effect of oxidation method of AlO[sub x] in magnetic tunnel junction by high resolution transmission electron microscopy.

Authors :
Bae, Jun Soo
Shin, Kyung Ho
Lee, Hyuck Mo
Source :
Journal of Applied Physics. 5/15/2002 Part 1, 2 & 3, Vol. 91 Issue 10, p7947. 3p. 4 Black and White Photographs.
Publication Year :
2002

Abstract

The formation of the insulating A1O[sub x] tunnel barrier is a critical and sensitive process in magnetic tunnel junctions. Both the natural oxidation and the plasma oxidation methods were employed to fabricate the A1O[sub x] insulating layer in this study. In the natural oxidation, the A1 layer was exposed to pure oxygen gas at 20 Torr for up to 50 min to produce the A10[sub x] tunnel barrier. It was revealed by high resolution transmission electron microscopy that the oxidation occurred preferentially through the grain boundary of A1 grains. Also, the A10[sub x] grains expanded isotropically when fully oxidized, thereby making the surface of the A1O[sub x] layer modulated. In plasma oxidation, the oxygen plasma was used at 20 mTorr of pure oxygen gas for up to 30 s and the flat A10[sub x] layer formed uniformly on the A1 layer. It had sharp interfaces with the underlying metallic A1 and the rate of oxide layer growth decreased as the oxidation proceeded. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00218979
Volume :
91
Issue :
10
Database :
Academic Search Index
Journal :
Journal of Applied Physics
Publication Type :
Academic Journal
Accession number :
6666814
Full Text :
https://doi.org/10.1063/1.1447200