Reliability of magnetic tunnel junctions with a spinel MgAl2O4 film

Abstract

We investigated the stress-induced resistance drift and breakdown characteristics in MgAl2O4 (MAO)-based magnetic tunnel junctions (MTJs) with the MAO thickness of similar to 0.9 nm. The occurrence of trap sites around the tunnel barrier-electrode interfaces was characterised via interval voltage stress (IVS) and constant voltage stress (CVS) experiments, in which the occurrence of trap sites affects the resistance drift in IVS and time- dependent dielectric breakdown in CVS. The observed resistance drift ratios were almost the same for positive and negative applied voltages, indicating that the difference in the interface structure was negligibly small between the top and bottom MAO/CoFe interfaces in the MAO-based MTJs. More interestingly, the resistance drift ratios were very low compared with the results of a previous study on MgO-based MTJs. MAO- based MTJs is likely to be an effective alternative that can be used to improve MTJ device reliability.