Researchers Demonstrate Precisely 'Tunable' Nanowire Diameters

Ildar R. Musin, Dmitriy S. Boyuk, and Michael A. Filler

J. Vac. Sci. Technol. B 31, 020603 (2013);
doi:10.1116/1.4792660

A team of Georgia Tech researchers has taken nanowire growth to a whole new level - by demonstrating a user-programmable process for precisely tuning diameter.

Nanowires are rod-like structures with diameters on the order of a few nanometers, and they grow on substrates in much the same way that trees grow in the forest - from the ground up. "In general, nanowire diameter tends to be fixed, which limits their functionality and usefulness. There are many applications where different diameters along the length of a single nanowire would be beneficial," explains Michael A. Filler, assistant professor of Chemical & Biomolecular Engineering at Georgia Tech.

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Pushing the Envelope: New Findings Will Help Researchers Develop Next-Generation DRAM Memory

B. Kaczer, S. Clima, K. Tomida, B. Govoreanu, M. Popovici, M.-S. Kim, J. Swerts, A. Belmonte, W.-C. Wang, V. V. Afanas'ev, A. S. Verhulst, G. Pourtois, G. Groeseneken, and M. Jurczak

J. Vac. Sci. Technol. B 31, 01A105 (2013);
doi:10.1116/1.4767125

Society's insatiable need for faster, smaller processors to run our everyday electronics is pushing the limits of a key memory component of these devices called Dynamic Random Access Memory (DRAM). To achieve additional functionality and boost the performance of DRAM the enabling technologies must be scaled down while keeping the cost of memory the same. Recently, significant progress in the scalability of DRAM has been made, and now a team of researchers at Imec in Belgium has developed an approach that can push the technology to its ultimate scaling limits.Read more

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Replicating Nature: A new method to mimic the light-manipulating properties of butterfly wings

Mukti Aryal, Doo-Hyun Ko, John R. Tumbleston, Abay Gadisa, Edward T. Samulski, and Rene Lopez

J. Vac. Sci. Technol. B 30, 061802 (2012);
doi:10.1116/1.4759461

A butterfly's striking coloration is produced by the way light interacts with complex, three-dimensional microscopic structures on the surface of scales that cover its wings. One of the most compelling properties of these scales is that their vivid hues look the same at nearly every angle from which they are viewed. Scientists have been working to reproduce this property of butterfly wings using non-natural materials, but the complexity of the original structures makes them difficult to imitate using laboratory methods.Read more

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Beam Me Out, Scotty: Making an Improved Holographic Lab on a Chip Spectrometer

Cosimo Calò, Valeria Lacatena, Scott D. Dhuey, Stefano Cabrini, Sergey Babin, Christophe Peroz, Alexander Koshelev, Igor Ivonin, Alexander Goltsov, and Vladimir Yankov

J. Vac. Sci. Technol. B 30, 06FE01 (2012);
doi:10.1116/1.4750038

Lab on a chip (LOC) devices - microchip-size systems that can prepare and analyze tiny fluid samples with volumes ranging from a few microliters to sub-nanoliters - are rapidly revolutionizing how laboratory tasks such as diagnosing diseases and investigating forensic evidence are performed. More importantly, LOC applications are transforming chemical analysis systems from large, immobile machines in a "brick-and-mortar" laboratory into tiny, portable instruments that can be put to work directly in the field. Read more

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Controlling the Electronic Properties of Semiconductors: The Surprisingly Important Role of Point Defects

Leonard J. Brillson, Yufeng Dong, Filip Tuomisto, Bengt G. Svensson, Andrei Yu. Kuznetsov, Daniel Doutt, H. Lee Mosbacker, Gene Cantwell, Jizhi Zhang, Jin Joo Song, Z.-Q. Fang, and David C. Look

J. Vac. Sci. Technol. B 30, 050801 (2012);
doi:10.1116/1.4732531

Semiconductors are essential to the electronics industry, enabling tiny circuitsto be embedded in everything from cell phones to light-up shoes. The semiconductor zinc oxide (ZnO) is a low-cost, non-toxic candidate material for the next generation of opto- and microelectronics, but mysteries about its electronic behavior persist. Read more

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Enormous Shrinkage of Carbon Nanotubes by supersonic stress and Low-acceleration electron beam irradiation

Jun-ichi Fujita, Teppei, Takahashi, Ryuichi Ueki, Takeshi Hikata, Soichiro Okubo, Risa Utsunomiya, and Teruaki Matsuba

J. Vac. Sci. Technol. B 30, 03D105 (2012);
doi:10.1116/1.3694027

The quest began when one of Jun-ichi Fujita's students left for lunch without turning off the electron beam. Fujita's team, from Tsukuba University in Japan, had been testing the tensile strength of carbon nanotubes (CNTs), which have potential uses for a range of electronics applications. When the researchers came back from lunch, they found that the nanotube they had left simmering in a bath of low-energy electrons was much shorter than it had been, and that it had a curious accordion-like structure. Read more

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Patterning Under Pressure: Researchers Test a New Way to Manufacture Nanoscale Metal Patterns without the Need for a Vacuum

Seung Whan Lee, Hamidreza Zamani, Philip X.-L. Feng, and R. Mohan Sankaran

J. Vac. Sci. Technol. B 30, 010603 (2012); http://dx.doi.org/10.1116/1.3669523

Computers, cell phones, and many other electronic devices are made possible by tiny chips inscribed with nanoscale circuit patterns. Nanoscale patterns can also help scientists speed up chemical reactions and manipulate light, but the costs of producing the patterns can be high. Now a team of researchers from Case Western Reserve University, in Cleveland, Ohio, has demonstrated a new way to create tiny patterns that eliminates an expensive requirement of some other manufacturing processes: the vacuum. The team's new techniques could help pave the way to low-cost mass production of nanoscale patterned films at atmospheric pressure. Read More

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Keeping Up with Moore's Law Using Directed Self-assembly (DSA)

Chi-Chun Liu, Christopher J. Thode, Paulina A. Rincon Delgadillo, Gordon S. W. Craig, Paul F. Nealey, and Roel Gronheid

J. Vac. Sci. Technol. B 29, 06F203 (2011); http://dx.doi.org/10.1116/1.3644341

Moore's law, credited to computing pioneer Gordon Moore, states that the size of features on microchips shrinks by 70 percent every two years. This rapid pace has been made possible, in part, by improvements in the optical lithography techniques used to manufacture the chips. But now one of the most commonly used techniques, called 193i, has reached the limit of its resolution capabilities. Coming to the rescue, potentially, is a technique called directed self-assembly (DSA). While researchers continue to develop next-generation technology to take the place of 193i, DSA promises to be an inexpensive and relatively uncomplicated interim solution for making smaller microchip features. Read More

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Fabrication and performance of graphene nanoelectromechanical systems

Robert A. Barton, Jeevak Parpia, and Harold G. Craighead

J. Vac. Sci. Technol. B 29, 050801 (2011)
doi:10.1116/1.3623419

As a result of the recent progress in fabricating large-area graphene sheets, graphene-based mechanical devices have become vastly easier to manufacture and now show even greater promise for a range of applications. This article reviews the progress of resonant graphene nanoelectromechanical systems and the possible applications of this technology to signal processing, sensing, and other areas. After discussing recent advances in fabrication and measurement techniques that make graphene resonators a viable technology, the article presents what is known about the performance of graphene mechanical systems. The authors also highlight unresolved questions, such as the source of the dissipation in graphene resonators, and discuss the progress made on these issues to date. The authors conclude with a discussion of important future directions for graphene research and the applications for which graphene nanomechanical devices may be well suited. Read More

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Plasma-polymer interactions: A review of progress in understanding polymer resist mask durability during plasma etching for nanoscale fabrication

Gottlieb S. Oehrlein, Raymond J. Phaneuf, and David B. Graves

J. Vac. Sci. Technol. B 29, 010801 (2011)
doi:10.1116/1.3532949

Advanced lithographic patterning of organic resist images followed by the transfer of resist patterns using plasma etching techniques into semiconducting, dielectric, conductive materials or matter with other functionalities/properties are the basis of the information technology, microsystems, and other current or developing technologies. One of the least understood elements of this approach is the interaction of the plasma species with the organic molecules representing the image, and the chemical, morphological and topographic changes induced by these interactions in the macromolecules themselves and the macromolecule defined nanoscale features. In this review the authors examine published observations and the scientific understanding that is available on factors that control etching resistance and dimensional stability of resist templates in plasma etching environments. Both materials parameters, e.g. polymer structure and composition, and plasma properties, e.g. role of ions, plasma-generated UV radiation, neutrals and energy deposition are considered. Resist template deformations seen after plasma processing such as surface and line edge roughness are related to experimental and computational studies of plasma or beam induced surface and near-surface modifications of model resists and polymers.

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