Thermal stability of Ir-Mn∕Co-Fe-B∕Al-O∕Co-Fe-B tunnel junctions

Abstract

Articles you may be interested in 80% tunneling magnetoresistance at room temperature for thin Al-O barrier magnetic tunnel junction with CoFeB as free and reference layers J. Appl. Phys. 101, 09B501 (2007) ͑thick-nesses unit in nanometers͒ has been investigated. The tunnel magnetoresistance ͑TMR͒ shows a large increase up to 54.4% after annealing at 265°C due to the improved characteristic properties of the barrier and the interface between the barrier and the ferromagnetic electrodes. The TMR was observed to decrease drastically above the annealing temperature of 310°C accompanied by a notable increase of junction resistance and coercivity of the free layer. The amorphous Co 62 Fe 20 B 18 layers seem to behave as a barrier of diffusion, preventing the migration of Mn or Cu atoms into the interface between the barrier and the ferromagnetic layers. This may cause the drastic decrease of TMR due to the deterioration of the barrier and its interface with Co 62 Fe 20 B 18 layers. The observed crystallization in the amorphous Co 62 Fe 20 B 18 layers is considered to contribute to the increase in coercivity of the free layer.

Repair effect on patterned CoFeB-based magnetic tunneling junction using rapid thermal annealing

“…Most MTJs show an MR trending to zero after 350 or 400 1C annealing [7,8]. Rapid annealing caused less damage than conventional annealing, as shown in Figs.…”

Magnetism in Co80-xFexB20: Effect of crystallization

“…Diffraction peaks start to appear in the spectrum for T a > 300 C (not shown), indicating the onset of the crystallization process, consistent with the literature. 17 For T a ¼ 450 C, the observed diffraction peaks for Co 80Àx Fe x B 20 are rather broad. Based on several studies, the morphology of the annealed films can be imagined as polycrystalline with a large spread in grain size D embedded in an amorphous matrix.…”

“…1, the XRD intensity pattern for as-deposited and annealed (T a ¼ 450 C) samples is shown for the region of interest, where diffraction peaks are known to appear for crystallized Co 80Àx Fe x B 20 . [16][17][18][19] We have chosen to limit our XRD analysis to relatively thick films of t ¼ 70 nm to obtain a sufficient signal to noise ratio. In the as-deposited case, as expected for an amorphous film, we do not observe any diffraction peaks other than from the Si substrate over a large range of diffraction angles (a representative measurement for x ¼ 80 is shown).…”

Effect of field-annealing on magnetostriction and tunneling magnetoresistance of Co/AlOx/Co/IrMn junctions

“…Tolerance to high temperatures is important in read head sensors and magnetoresistance random access memory (MRAM) [1][2][3].…”