Presentation Information
[17a-M_374-3]Annealing condition dependence of electrical 1/f noise in magnetic tunnel junctions with Mg-Al-O barrier
〇Haoxiang He1, Chaoliang Zhang1, Mikihiko Oogane1,3, Takafumi Nakano1,2, Yupeng Wang1 (1.Tohoku Univ., 2.Green X-Tech, Tohoku Univ., 3.CSIS, Tohoku Univ.)
Keywords:
magnetic tunnel junction,tunnel magnetoresistance,1/f noise
Magnetic tunnel junction (MTJ) based tunnel magnetoresistance (TMR) sensors have significant potential for biomedical and weak field sensing applications, where electrical 1/f noise limits device performance. This noise primarily arises from charge trapping and detrapping at defects within the tunnel barrier and its interfaces. Compared with conventional MTJs with MgO barriers, Mg Al O (MAO) barriers exhibit better lattice matching with Fe based electrodes and have been reported to reduce electrical 1/f noise by nearly one order of magnitude. However, the relationship between annealing conditions and electrical 1/f noise remains unclear.
Here, we investigate the impact of annealing temperature on the electrical 1/f noise characteristics of MTJs with MAO barriers. The MTJ stacks are deposited on Si SiO2 substrates by magnetron sputtering. Following MAO deposition, annealing is performed at TMAO = RT, 300 C, and 450 C. After stack completion and micropatterning, post annealing Ta is performed for 1 hour under a 1 T external magnetic field. Electrical 1/f noise is evaluated using a four probe configuration and quantified by the Hooge parameter alpha_ele.
The results indicate that alpha_ele for samples with low TMAO (RT and 300 C) exhibits a non monotonic dependence on Ta, reaching minimum values of about 1.1e-9 um2 (TMAO = RT) and 1.3e-9 um2 (TMAO = 300 C) at Ta around 350 to 375 C. In contrast, the TMAO = 450 C sample shows a significantly weaker Ta dependence. STEM and EDX analyses reveal that increasing Ta improves the crystallinity and structural uniformity of the MAO barrier, CoFeB layers, and their interfaces. While the top MAO CoFeB interface becomes optimally ordered at Ta around 35_
Here, we investigate the impact of annealing temperature on the electrical 1/f noise characteristics of MTJs with MAO barriers. The MTJ stacks are deposited on Si SiO2 substrates by magnetron sputtering. Following MAO deposition, annealing is performed at TMAO = RT, 300 C, and 450 C. After stack completion and micropatterning, post annealing Ta is performed for 1 hour under a 1 T external magnetic field. Electrical 1/f noise is evaluated using a four probe configuration and quantified by the Hooge parameter alpha_ele.
The results indicate that alpha_ele for samples with low TMAO (RT and 300 C) exhibits a non monotonic dependence on Ta, reaching minimum values of about 1.1e-9 um2 (TMAO = RT) and 1.3e-9 um2 (TMAO = 300 C) at Ta around 350 to 375 C. In contrast, the TMAO = 450 C sample shows a significantly weaker Ta dependence. STEM and EDX analyses reveal that increasing Ta improves the crystallinity and structural uniformity of the MAO barrier, CoFeB layers, and their interfaces. While the top MAO CoFeB interface becomes optimally ordered at Ta around 35_