Influence of Boron Diffusion on Transport and Magnetic Properties in CoFeB/MgO/CoFeB Magnetic Tunnel Junction

Author

Park, Chando ; Miloslavsky, Lena ; Lim, Ira ; Oh, Sangmun ; Kaiser, Christian ; Leng, Qunwen ; Pakala, Mahendra

Author_Institution

Western Digital Corp., Freemont, CA, USA

Volume

45

Issue

10

fYear

2009

Firstpage

3457

Lastpage

3459

Abstract

Influence of boron concentration in CoFeB on the transport properties of CoFeB (B 20% and B 16%)/MgO/CoFeB magnetic tunnel junction (MTJ) was investigated. Boron distribution was studied by using X-ray photoelectron spectroscopy (XPS). High-resolution transmission electron microscope was utilized for analysis of the texture and interface quality. The MTJ with the boron diluted CoFeB (B 16%) pinned layer shows 10% higher MR than the CoFeB (B 20%). HRTEM shows that the MgO/CoFeB interface for the sample with diluted CoFeB layer has a better epitaxial MgO/CoFeB growth. Higher boron concentration in the as-deposited CoFeB stays high after annealing but boron content in the MgO increases as well. These results suggest that that MR improvement is directly related to the distribution of the boron in CoFeB/MgO/CoFeB MTJs after annealing.

Keywords

X-ray photoelectron spectra; annealing; boron; boron alloys; cobalt alloys; diffusion; iron alloys; magnesium compounds; magnetic epitaxial layers; magnetic multilayers; magnetic tunnelling; magnetoresistance; metal-insulator boundaries; texture; transmission electron microscopy; CoFeB-MgO-CoFeB; HRTEM; MTJ; X-ray photoelectron spectroscopy; XPS; annealing; boron diffusion; epitaxial growth; high-resolution transmission electron microscopy; magnetic properties; magnetic tunnel junction; magnetoresistance; pinned layer; texture; transport properties; Boron; MgO barrier; crystallization; magnetic tunnel junction (MTJ); magnetoresistance;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2009.2022495

Filename

5257309