Macedo R.,INESC Mlcrosystems and Nanotechnologies |
Macedo R.,University of Lisbon |
Borme J.,INESC Mlcrosystems and Nanotechnologies |
Ferreira R.,INESC Mlcrosystems and Nanotechnologies |
And 7 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2010
In this paper the electron-beam lithography conditions and the nanofabrication process are described for current-perpendicular-to-plane (CPP) pillar devices with 30 nm critical dimensions. This work combines a RAITH-150 tool with a negative e-beam resist (AR-7520) so that dense nanopillar arrays are patterned fast into large area samples. The resist dilution and coating con-ditions are optimized, aiming at its thickness reduction down to 80 nm. The exposure parameters are tuned for different geometries and dimensions, so that features down to 30 nm are exposed with good accuracy (±1.9 nm) and reproducibility. The complete integration of these nanoelements into CPP devices involved electron beam lithography, ion milling for pattern transfer and chemical-mechanical polishing (CMP). Results on devices incorporating very low resistance-area (R × A) MTJ films deposited by Ion beam assisted deposition are shown, for MTJ stacks with R x A down to 0.8 ilfim2. Device characterization includes electrical measurement of the pillar resistance and the transfer curves under dc magnetic fields (TMR up to 40%).© 2010 American Scientific Publishers.