Nanolithography Method Research Articles

Microrefrigeration by quasiparticle tunnelling in NIS and SIS junctions

A solid-state refrigeration method at sub-kelvin temperatures has been developed. It is based on quasiparticle tunnelling between a superconductor and a normal metal, or, between two dissimilar superconducting metals. The refrigerator is fabricated by combining nanolithography and micromachining methods. This technique has been demonstrated in both electron cooling from 0.3 to 0.1 K and in refrigeration of a dielectric platform. We describe a new fabrication method of tunnel junctions in a shadow evaporation configuration using a mechanical mask of silicon nitride.

Nanopatterning Phospholipid Bilayers

A nanolithography method for altering the composition of supported phospholipid bilayers has been developed. Although a number of lithography procedures for various chemical systems currently exist, these methods typically rely on covalent bonding to stabilize the resulting structure. The method described here is suitable for an entirely noncovalent system, where the pattern is maintained by specific hydrophobic and other noncovalent interactions. This lithography is achieved by the atomic force microscope, which is used to insert phospholipid molecules into a supported reconstituted high-density lipoprotein−phospholipid bilayer with 20 nm line widths. Lipid molecules are delivered to the supported bilayer through transient structural disruption, forcing the acceptance of new lipid monomers into the bilayer structure. Precoating the atomic force microscope tip with specific lipids is sufficient to deliver new lipid to the patterned areas. These results demonstrate a new method for controlling the structur...

Imprint of sub-25 nm vias and trenches in polymers

A nanoimprint process that presses a mold into a thin thermoplastic polymer film on a substrate to create vias and trenches with a minimum size of 25 nm and a depth of 100 nm in the polymer has been demonstrated. Furthermore, the imprint process has been used as a lithography process to fabricate sub-25 nm diameter metal dot arrays of a 100 nm period in a lift-off process. It was found that the nanostructures imprinted in the polymers conform completely with the geometry of the mold. At present, the imprinted size is limited by the size of the mold being used; with a suitable mold, the imprint process should mold sub-10 nm structures with a high aspect ratio in polymers. The nanoimprint process offers a low cost method for mass producing sub-25 nm structures and has the potential to become a key nanolithography method for future manufacturing of integrated circuits and integrated optics.

Nanostructure technology

The ability to fabricate structures with lateral dimensions in the sub-100-nm range has opened a new field of research. This paper first reviews recent advances in nanolithography techniques, with a brief discussion of their relative merits and fundamental limits. Special emphasis is given to the scanning electron-beam method, which is the most widely used nanolithography method at the present time. The two main areas of nanostructure research are device technology and basic science. Highlights of a number of exploratory programs in these two areas are presented.