Magnetic Tunnel Junctions Fabricated Using Ion Neutralization Energy as a Tool
Joshua M. Pomeroy, Holger Grube, Pei-Ling Sun, Yun-Che Wang, Russell E. Lake
The neutralization energy of highly charged ions (HCIs) is used as an intermediate processing step to modify the electrical properties of magnetic tunnel junctions (MTJs), providing an additional degree of freedom in the devices fabrication. While most ion species used in common semiconductor processes (like implantation or plasma cleaning/oxidation) have negligible neutralization energies, the HCIs utilized in this work carry as much as 52 keV per HCI of neutralization energy, ample to modify the chemical and electrical properties of the tunnel barriers at the impact site. Hundreds of MTJ devices have been fabricated, revealing some general characteristics of the HCI modified tunnel junctions: the electrical conductance increases linearly with the number of HCIs used; the conductance added per HCI depends on the tunnel barrier thickness, the barrier stoichiometry, and the HCI charge state; in most cases studied, the transport characteristic remains tunneling (vs. diffusive); and the conductance added by the HCI process can substantially increase the magneto-conductance.
August 2-6, 2010
Ft. Worth, TX
CAARI 2010 - 21st International Conference on the Applicationof Accelerators in Research and Industry