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Title: Nanofabrication

Abstract

Pathways to rapid and reliable fabrication of three-dimensional nanostructures are provided. Simple methods are described for the production of well-ordered, multilevel nanostructures. This is accomplished by patterning block copolymer templates with selective exposure to a radiation source. The resulting multi-scale lithographic template can be treated with post-fabrication steps to produce multilevel, three-dimensional, integrated nanoscale media, devices, and systems.

Inventors:
; ; ;
Publication Date:
Research Org.:
University of Massachusetts, Boston, MA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1176141
Patent Number(s):
7,189,435
Application Number:
10/098,222
Assignee:
University of Massachusetts (Boston, MA) OSTI
DOE Contract Number:
FG02-96ERA45612
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE

Citation Formats

Tuominen, Mark, Bal, Mustafa, Russell, Thomas P., and Ursache, Andrei. Nanofabrication. United States: N. p., 2007. Web.
Tuominen, Mark, Bal, Mustafa, Russell, Thomas P., & Ursache, Andrei. Nanofabrication. United States.
Tuominen, Mark, Bal, Mustafa, Russell, Thomas P., and Ursache, Andrei. Tue . "Nanofabrication". United States. doi:. https://www.osti.gov/servlets/purl/1176141.
@article{osti_1176141,
title = {Nanofabrication},
author = {Tuominen, Mark and Bal, Mustafa and Russell, Thomas P. and Ursache, Andrei},
abstractNote = {Pathways to rapid and reliable fabrication of three-dimensional nanostructures are provided. Simple methods are described for the production of well-ordered, multilevel nanostructures. This is accomplished by patterning block copolymer templates with selective exposure to a radiation source. The resulting multi-scale lithographic template can be treated with post-fabrication steps to produce multilevel, three-dimensional, integrated nanoscale media, devices, and systems.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Mar 13 00:00:00 EDT 2007},
month = {Tue Mar 13 00:00:00 EDT 2007}
}

Patent:

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  • The author has developed a new and controllable nanofabrication technique, photo-nanofabrication, based on near-field photo-chemical synthesis and nanometer optical sources. Photo-nanofabrication can produce subwavelength light and exciton probes with or without specific chemical or biological sensitivity. By applying near-field optics, the author has successfully demonstrated a new concept of near-field photochemical synthesis, in which the dimension of a product is solely determined by the size of the light source. The most successful application to date is the development of the smallest fiberoptic chemical sensors. Specifically, a thousandfold miniaturization of an immobilized fiberoptic pH sensor has been achieved, leading to atmore » least a millionfold decrease in necessary sample volume and to at least a hundredfold shorter response time. The sensors have high fluorescence intensity and excellent detection limit. New internal calibration methods have also been developed for accurate pH quantification. The newly developed optical sensors have been used in real time measurements of pH on individual, viable, intact rat conceptuses during the period of organogenesis. The sensors can discriminate pH changes of less than 0.1 pH unit in the physiologic pH range. Static determinations of pH in rat conceptuses of varying gestational ages show decreasing pH with conceptal age. Chemical dynamic alterations in pH of intact rat conceptuses, in response to several variations in their environmental conditions, have been measured. Passive and active subwavelength light sources have been constructed with both micropipettes and fiberoptic tips. They have been used as exciton and light sources and in preliminary probe-to-sample distance regulated, Foerster energy transfer studies as well as in studies of the probe-to-sample interfacial Kasha effect. They were also used in supertip development for near-field scanning optical microscopy and for molecular exciton microscopy.« less
  • A single-etch-step process for the fabrication of high-efficiency diffractive optical elements is presented. The technique uses subwavelength surface relief structures to create a material with an effective index of refraction determined by the fill factor of the binary pattern. Fabrication is performed using electron beam lithography and reactive-ion-beam etching on bulk GaAs, but the process is applicable to any material for which well-controlled etches exist. In this work, we designed and fabricated a blazed transmission grating for operation at 975 nm. The blazed grating exhibits a diffraction efficiency into the first order of 85% of the transmitted power. {copyright} {italmore » 1995} {ital American} {ital Vacuum} {ital Society}« less
  • One step required for the fabrication of a quantum dot array on an aluminum substrate is the preparation of a flat aluminum surface. To enable the optimization of the electropolishing procedure, atomic force microscopy was used to examine the morphology of electropolished polycrystalline aluminum surfaces that were prepared under different electropolishing conditions. The electropolishing voltage, time, and temperature were varied. Two distinctly different surface morphologies were observed for different electropolishing conditions and transitional structures were observed for intermediate conditions. It was found that the type of surface morphology and the surface roughness could be controlled primarily with the electropolishing voltagemore » while temperature and time had relatively little effect over the range examined in this study. 30 refs., 11 figs., 2 tabs.« less
  • Nanostructures are defined to be ultrasmall structures and devices with dimensions less than or equal to 100 nm. Conventional methods for making thin film structures involve exposure of a thin layer of a polymer resist on a suitable substrate to define a pattern, which is then developed and used to fabricate the structures either by deposition, or by etching. Resistless methods of patterning, followed by epitaxial growth could significantly simplify nanofabrication by eliminating a number of processing steps associated with the application, exposure, development, and removal of the resist. The molecular size effect with polymer based resists such as PMMAmore » is believed to be a significant factor in limiting the resolution (grain size) in electron beam lithography (EBL) to 10 nm. Surface adsorption layers such as the hydride layer on the Si surface are characterized by relatively strong chemical bonding which produces a highly uniform coverage that terminates at a single monolayer. Because of these properties surface adsorption layers are attractive candidates as ultrathin, ultrahigh resolution resists for electron beam patterning. In this paper, the authors report on results concerning electron beam induced patterning of the surface hydride layer on silicon, using a scanning electron beam lithography (SEBL) system. The dependence of the linewidth on accelerating voltage, electron exposure dose, and sample thickness was explored to determine the mechanisms that govern pattern formation. The results achieved with silicon hydride have general significance and are believed to be applicable to other adsorption layer/substrate combinations. The objective of this research is to artificially generate ultrahigh resolution lateral chemical selectivity on the growing surface which is to be used in subsequent epitaxial growth of nanostructures in a process known as selective area epitaxy (SAE).« less
  • The Precision Engineering Center has recently begun a research program into applications of STM to Nanotechnology. Few tools permit humans to control events and processes at the manometer level, and of those, the STM is the most well-suited to the task. A versatile new ultra-high-vacuum (UHV) STM is being built to study the use of STM for the manipulation of nanometer-scale particles. Part of the STM`s usefulness will be due to its being positioned directly beneath the focused ion beam (FIB). The interface of the STM with the FIB will allow the STM to take advantage of the FIB formore » long-range imaging and as a particle source; the FIB can in turn use the STM for in situ, high-resolution imaging of micromachined features.« less