CoFeB/MgO 磁気トンネル接合のキャップ層としてのTa-N ならびに Ti-N 薄膜の作製

抄録

  We investigated the compatibility of Ta-N and Ti-N thin films as a capping layer of CoFeB/MgO magnetic tunnel junctions on the basis of their resistivity, crystal structure, thermal stability and absorbability of boron. Ta-N and Ti-N thin films were prepared on MgO(001)/CoFeB structure by reactive sputtering using a gas mixture of Ar and N₂ with varying N₂ percentage (f_N2). It was found that Ti-N prepared at f_N2=30% had a resistivity of 220 μΩ cm, a nanocrystalline structure, a high thermal stability and good absorbability of boron compared with conventional Ta. These results suggest that Ti-N has potential as a novel capping material for CoFeB/MgO magnetic tunnel junctions.