Tech Briefs

GMR materials can be patterned to line widths of tens of nanometers.

Rings of a GMR Material having inner diameter of 80 nm and outer diameter of 240 nm were fabricated in the nanolithographic process described in the text.
The figure shows an example of rings of a GMR material fabricated in this process. The best resolution attainable when electron- beam- lithography was used for patterning was found to characterized by a line width of about 30 nm. It was found that patterning by use of the focused Ga+ beam could be accomplished about 10 to 100 times as fast as by electron-beam lithography, but with somewhat poorer resolution characterized by a line width between 30 and 40 nm and rougher feature edges. [It should be noted that a GMR material could also be patterned directly (that is, without a resist mask) to desired shape and size by focused-ion-beam sputtering, but the GMR properties would likely be degraded.]

Another topic addressed in this work was increasing throughput in lithographic processing. One promising approach is ultra-rapid patterning of poly(methyl methacrylate) resist by sputtering induced by focused 30-keV beams of Ga+ ions.

Yet another topic addressed in this work was fabrication of semiconductor nanowires and associated structures. Advances in this area are important for the development of quantum cellular automata and other devices based on quantum dots.

This work was done by R. Hull, L. Harriott, P. Parrish; C. Chen, S. Liu, J. Graham, L. He, M. Smith of the University of Virginia; G. Snider and A. Prager of Notre Dame University; and L. Samuelson, J. Johanson, S. Nilison, and L. Montelius of Lund University for the Naval Research Laboratory.

NRL-0020

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