Depth analysis of boron diffusion in MgO/CoFeB bilayer by x-ray photoelectron spectroscopy

Y. Lu, B. Lépine, G. Jézéquel, S. Ababou, M. Alnot, J. Lambert, A. Renard, M. Mullet, C. Deranlot, H. Jaffrès, F. Petroff, J.-M. George
2010 Journal of Applied Physics  
We have studied the boron ͑B͒ diffusion in MgO/CoFeB bilayer by x-ray photoelectron spectroscopy depth analysis. A large concentration of B ͑B / Mg= 0.16͒ was found to diffuse into the MgO barrier after 350°C annealing. The boron in MgO is in a highly oxidized B 3+ state and is homogenously distributed in the whole barrier. The important B diffusion in MgO could be related to the CoFeB crystallization process which begins from the under CoFeB/Ru interface and pushes boron atoms to diffuse into the MgO barrier during annealing.
doi:10.1063/1.3465308 fatcat:cez46rewkrgefjvxsy2dnlw47a