Effect of Mg insertion on stress-induced resistance drift in MgO-based magnetic tunnel junctions

Abstract

The stress-induced resistance drift in MgO-based magnetic tunnel junctions (MTJs) with Mg insertion layer above and below a MgO tunnel barrier is investigated. Mg insertion suppresses the resistance drift. Resistance drift characteristics are improved when electrons tunnel into the Mg-inserted barrier-electrode interface, indicating that Mg insertion significantly suppresses trap site formation at the anode-side barrier-electrode interface. However, transmission electron microscopy images confirm that there is little difference in interface crystallinity between the Mg-inserted and non-inserted interfaces. Therefore, it is shown that a slight modification of the barrier-electrode interface states has a significant impact on resistance drift characteristics, and Mg insertion on both interface sides appears to be an effective way to improve MTJ device reliability in practical applications.