In-situ characterization of rapid crystallization of amorphous CoFeB electrods in CoFeB/MgO/CoFeB junctions during thermal annealing.

Journal Article · Mon Dec 14 04:00:00 EST 2009 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3273397· OSTI ID:1041133

Wang, W G; Rumaiz, A; Jordan-sweet, J; Miao, G X; Ni, C; Sha, L R; Fan, X; Parsons, P; Stearrett, R; Nowak, E R; Moodera, J S; and Xiao, J Q

We report the crystallization study of CoFeB/MgO/CoFeB magnetic tunnel junctions using in-situ, time-resolved synchrotron-based x-ray diffraction and transmission electron microscopy. It was found that the crystallization of amorphous CoFeB electrodes occurs on a time scale of seconds during the postgrowth high temperature annealing. The crystallization can be well fit by the Johnson-Mehl-Avrami model and the effective activation energy of the process was determined to be 150 kJ/mol. The solid-state epitaxy mode of CoFeB was found to involve separate crystallization at different locations followed by subsequent merging of small grains, instead of layer-by-layer growth of CoFeB film along the MgO template.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1041133
• Report Number(s): BNL--90919-2010-JA; BR0204011
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 24 Vol. 95; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
ANNEALING
BORON ALLOYS
COBALT ALLOYS
CRYSTALLIZATION
ELECTRODES
EPITAXY
IRON ALLOYS
MAGNESIUM COMPOUNDS
MAGNETIC MATERIALS
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION