Influence of the MgO barrier thickness on the lifetime characteristics of magnetic tunnelling junctions for sensors. (4th May 2016)

• Record Type: Journal Article
• Authors: Conca, A; Casper, F; Paul, J; Lehndorff, R; Jakob, G; Kläui, M; Hillebrands, B; Leven, B
• Is Part Of: Journal of physics. Volume 49:Number 22(2016)
• Publication Date: 2016-05-04
• Subjects: sensors -- reliability -- magnetic tunnelling junctions -- lifetime -- Weibull; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/49/22/225001
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Magnetic tunnelling junctions increasingly enter the market for magnetic sensor applications. Thus, technological parameters such as the lifetime characteristics become more and more important. Here, an analysis of the lifetime characteristics of magnetic tunnelling junctions using the Weibull statistical distribution for CoFeB/MgO/CoFeB junctions is presented. The Weibull distribution is governed by two parameters, the characteristic lifetime η of the population and the shape parameter β, which gives information about the presence of an infant mortality. The suitability of the Weibull distribution is demonstrated for the description of dielectric breakdown processes in MgO-based tunnelling junctions at different voltages. A study of the dependence of the characteristic lifetime extrapolated to the low voltage regime, and the β parameter on the nominal barrier thickness and the resistance × area product of the MgO barrier is shown. The influence of the RF deposition power for the MgO barrier and an annealing step on the Weibull parameters is also discussed.