Fabrication of large area nano-rings for MRAM application

We have developed lateral etch techniques to fabricate large area high density nano-scale magnetic ring arrays by deep ultraviolet lithography. Both centered and de-centered rings have been obtained. The width of the rings are controlled by the lateral etch time, and the inner ring diameter was scaled down below the lithography resolution limit. For de-centered rings, the shift between the center of inner and outer circles was easily adjustable. The characteristics of the ring arrays were characterized by SEM, AFM and SQUID.