Characterization of Conducting Atomic Force Microscopy for Use With Magnetic Tunnel Junctions

In this paper we quantify the electrical properties of magnetic tunnel junctions with conducting atomic force microscopy (CAFM). Using rectangular pillars patterned on a magnetic tunnel junction film with in plane anisotropy, we examine the repeatability of CAFM measurements on the same pillar. We also quantify the variability seen across over 200 different pillars of sizes ranging from 600 nm × 300 nm down to 100 nm × 50 nm. By field switching the pillars, we quantify the contribution of the probe and contact resistance independent of the lithographic variation contribution to the resistance variation. Greater than 99% of the pillars lithographically patterned were functional for field switching and CAFM readback. While the smallest pillars studied (100 nm × 50 nm) show the largest fluctuations in resistance, these pillars are actually the closest to meeting the requirement of 12 standard deviation separation between the high and low resistance values.