Surface flattening processes of metal layer and their effect on transport properties of magnetic tunnel junctions with Al-N barrier

Journal Article · Sun May 15 04:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1854452· OSTI ID:20709702

Yoshimura, S; Nozawa, T; Shoyama, T; Tsunoda, M; Takahashi, M ^[1]

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1. Department of Electronics Engineering, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba-yama, Sendai 980-8579 (Japan)

In order to form ultrathin insulating layer in magnetic tunnel junctions (MTJs), two surface flatting processes of metal films are investigated. Oxygen-additive sputter-deposition process was applied to the bottom Cu electrode and the Al layer to be nitrided. Dry-etching process was applied for the surface treatment of lower Co-Fe layer. As a result, the surface roughness of stacked ultrathin Al layer to be nitrided is reduced from 3.2A to 1.7A, and the tunnel magnetoresistance (TMR) ratio of the MTJs increases from 1% to 26% while maintaining resistance-area product (RxA) less than 5x10{sup 2} {omega} {mu}m{sup 2} in the Co-Fe/Al(6A)-N/Co-Fe MTJs. We conclude that the decrease of the surface roughness of Al layer is one of the key factors to realize high performance MTJs with low RxA and high TMR ratio.

• OSTI ID: 20709702
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 10 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADDITIVES
ALUMINIUM
ANNEALING
CHARGED-PARTICLE TRANSPORT
COBALT
DEPOSITION
ELECTRODES
ETCHING
FERROMAGNETIC MATERIALS
IRON
LAYERS
MAGNETISM
MAGNETORESISTANCE
OXYGEN
ROUGHNESS
SUPERCONDUCTING JUNCTIONS
SURFACE TREATMENTS
THIN FILMS
TUNNEL EFFECT