Evaluation of MFM for probing electromigration processes

Abstract

The study of electromigration in metals requires correlation of current densities with the evolution of defects in current-carrying lines. In principle, magnetic force microscopy (MFM) is an appropriate probing tool that will allow us to directly image the curvature of the magnetic fields around defect structures and thus deduce the underlying current densities. Previous use of MFM in research has concentrated upon determining magnetic polarity, such as that across magnetic domain boundaries, and there has been little evaluation of MFM capability to make meaningful quantification. To explore the MFM capability to yield reliable analysis, we are carefully evaluating the MFM instrument response for known structures, such as that around lines containing defects of simple geometry. The instrumental response function is defined by tip parameters, such as tip magnetization and shape, which make absolute quantification impractical, but it is possible to make meaningful relative quantification and calibration, by...