NEWS FROM THE WORLD OF MATERIALS

Visit the Materials360 Plus^® and the Materials News pages on the MRS Website for continually updated research news and features

Image in Focus

Nano Spaghetti & Meatballs
Colorized and overlaid scanning electron microscope images of "Spaghetti & Meatballs" made out of Au and Si. The 'spaghetti' is a collection of electrodeposited Au nanowires, 100 nm in diameter, that have been released from the substrate and bundled together. The 'meatballs' are Si nanoparticles, ~1.5 um in diameter, with Au nanocrystals on the surface that were grown on carbon-coated substrates using ultra-high vacuum molecular beam epitaxy.

(One of three first place winners of the the Science as Art competition at the 2009 MRS Spring Meeting. Submitted by Blythe G. Clark, Sandia National Lab., and Dan Gianola, Forschungszentrum Karlsruhe GmbH)

[We invite you to submit your images to the Editor for possible inclusion in this feature]

Materials in Focus

Electric field acts as a switch in a multiferroic
Multiferroics are potential cornerstones in future magnetic data storage and spintronic devices, provided a simple and fast way can be found to turn their electric and magnetic properties on and off. A research group working with a prototypical multiferroic has successfully demonstrated just such a switch -- electric fields. Using electric fields, they were able to create, erase and invert p–n junctions in a calcium-doped bismuth ferrite multiferroic film.

Gold nanorods boost capacity of next-generation optical disks 
Traditional DVDs and Blu-ray optical disks store data in two dimensions and there's been a recent push to increase their capacity by creating multi-layered disks that store data across three dimensions. Researchers are now stepping into hyperspace, by encoding information in two new dimensions — the wavelength and polarization of the laser light used to write the data. The key was to find a material for the disk that could store this extra information. The ideal material contains gold, rod-shaped nanoparticles of different sizes and orientations. The team has demonstrated that by using two polarizations and three colors, one can pack 1.6 terabytes of data in one DVD-sized disk. A Blu-ray disk, by comparison, can store around 50 gigabytes. Adding an extra dimension by using another polarization could ramp that up further to 7.2 terabytes.

Carbon atomic wires obtained from graphene 
Researchers show that using a high-energy electron beam, they can transform graphite into graphene, and further into separate strings of carbon atoms in a transmission electron microscope. By focusing a high-energy, high-current beam on a spot on a carbon flake, they removed carbon atoms and thinned the flake until they were able to expose a single atomic carbon layer. Further irradiation at high energy and intensity produced two neighboring holes in the graphene layer, separated by a graphene nanoribbon, which they can continued to thin with more irradiation. At the last stage of narrowing the nanoribbon, when the two edges came together, the ribbon could be seen to break up into two parallel single-atom strands. The observed chains are longer than what has been previously observed, up to 2.1 nm, or 16 carbon atoms in a row.

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Novellus Advances PVD TaN Barrier Film

TOP STORY... May 28, 2009

Novellus said its has developed a conformal hollow cathode magnetron (HCM) PVD technology, called IONX XL, which provides the very thin barrier layers needed for the copper interconnects at the 3X node. The barrier film challenge is causing some companies to consider a shift from planar PVD to the more expensive CVD approach, but Novellus said it can extend PVD to the 3X generation. 
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Materials Engineers wants to keep up with you on Twitter

Materials Engineers wants to keep up with you on Twitter To find out more about Twitter visit http://twitter.com/i/9e97e0abd862c1f1cee9a845aadf80579adcdf79 Thanks, — The Twitter Team About Twitter Twitter is a unique approach to communication and networking based on the simple concept of status. What are you doing? What are your friends doing—right now? With Twitter, you may answer this question over SMS or the Web and the responses are shared between contacts. This message was sent by a Twitter user who entered your email address. If you'd prefer not to receive emails when other people invite you to Twitter you can opt-out

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Downturn to Spur Shift to 3-D Packaging

TOP STORY... May 27, 2009

The past several semiconductor downturns have resulted in transitions from one generation of packaging to the next. This one's no exception. "Out of this downturn, we're rapidly shifting from 2-D to 
3-D packaging," says Jim Walker, vice president of semiconductor manufacturing research at Gartner Inc. 
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Sanyo Pushes c-Si Solar Cell to 23% Conversion Efficiency

TOP STORY... May 26, 2009

Sanyo Electric Co. Ltd. has broken its own record for the highest energy conversion efficiency for a crystalline silicon solar cell in a practical size, beating its previous efficiency by almost a full percentage point. The cell is a hybrid cell composed of a single thin c-Si wafer sandwiched by ultrathin amorphous silicon (a-Si) layers. The structure minimizes defects within the p/n junction of the cell, producing higher-efficiency cells while producing more power even at higher temperatures.
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Flip-Chip Packaging Becomes Competitive

TOP STORY... May 19, 2009

Flip-chip packaging is gradually replacing the once-dominant wire-bonded technology in products ranging from digital cameras to servers, writes Contributing Editor Sally Cole Johnson in the May issue of Semiconductor International. Flip-chip's appeal is increasing as its cost competitiveness with wire bonding improves in the 200–700 pin count range. The primary technical benefits include size savings, shorter path lengths with low inductance, high I/O density, rework capability, self-alignment and superior thermal management.
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Infrastructure Still Inhibits 3-D ICs

TOP STORY... May 20, 2009

Contributing Editor Ruth DeJule examines the status of 3-D technologies, including obstacles that may be slowing down the commercialization process. "The industry is debating between wafer-to-wafer and die-to-wafer stacking, with the process requirements of high assembly yield, and low complexity and cost," DeJule writes. "The choice will be determined based on application and economic grounds." 
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Metrologists: Measure Twice, Process Once

TOP STORY... May 18, 2009

IBM's T.C. Chen, Alain Diebold of CNSE, and J. Alexander Liddle of NIST were among the metrology experts who spoke at the 2009 International Conference on Frontiers of Characterization and Metrology for Nanoelectronics. "Dimensions are approaching atomistic and quantum mechanical boundaries," said Chen, vice president of science and technology at IBM's T.J. Watson Research Center, adding that scaling already has resulted in increasing power dissipation, device variability, and degraded device and interconnect performance. 
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NEWS FROM THE WORLD OF MATERIALS

- from Materials Research Society,

• Nitrogen n-dopes graphene
• Two metals better than one for fuel cell catalysts
• Core structure suppresses blinking in quantum dots
• Smallest incandescent lamp uses single C-nanotube
• DNA twisted into boxes
  more....

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Materials in Focus

- from  Materials Research Society,

Nitrogen n-dopes graphene

It is relatively easy to p-dope graphene using adsorbates and oxygen groups on edges, but for real-world applications, scientists need to be able to make n-doped material too. This is more difficult because special strategies are needed. A research team has now shown that graphene can be n-doped through high-power electrical joule heating in ammonia gas. They then made an n-type graphene FET that operates at room temperature.

Weak light beam flips magnetization in magnetic semiconductor
A research team has showed that a surprisingly feeble light beam can flip zeros to ones and vice versa, in a special magnetic layer. Although currently limited to very low temperatures, the apparently new effect might one day be extended to improve data storage. They grew a thin, crystalline layer of the gallium arsenide but replaced about one percent of the gallium atoms with the magnetic atom manganese.

Polymers indicate imminent failure by changing color
A new polymer changes color when stressed to the point of mechanical failure. The color change occurs by the addition of spiropyran molecules that undergo electrocyclic ring-opening in response to mechanical force. The resulting ring-opened merocyanine molecules are brightly colored, producing red or purple hues in the polymer, depending upon how the indicator molecule is covalently linked to the polymeric structure. The spiropyran essentially undergoes "a force-induced reaction inside of a solid structural polymer."

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Emtec Microscope Tilts Light Source

TOP STORY... May 12, 2009 for Semiconductor international

Japan-based Emtec Co. Ltd. has developed an optical microscope that uses a slightly tilted light source to observe transparent surfaces and other objects that are difficult to see with a conventional microscope. The microscope is targeted at viewing defects on ICs, molded packages, LCD surfaces, and transparent electrodes on LCDs, among others.
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Freescale Taking Nanocrystal Flash to Production

TOP STORY... May 11, 2009

After five years of technology development, Freescale said it is ready to move nanocrystal flash to the product stage for its MCU product line. At the International Memory Workshop (IMW) being held this week in Monterey, Calif., Freescale will detail progress in its nanocrystal flash development program, including reliability and cost advantages.
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Novellus Rolls UV-Absorbing Dielectrics

TOP STORY... May 7, 2009

Novellus said it has developed a dense ultralow-k and diffusion barrier stack that absorbs ultraviolet radiation from UV thermal processing steps. The UV-absorbing films protect the compressive strain that enhances device performance, Novellus said. The solution is being offered as an alternative to porous dielectric solutions.
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latest news from MaterialsToday

from MaterialsToday

Super battery! The storage of electrical energy at high charge and discharge rate is an important technology in today's society. It can enable hybrid and plug-in hybrid electric vehicles and provide back-up for wind and solar energy. April 30, 2009 Printable power using carbon nanotube supercapacitors Portable electronic devices such as mobile phones, netbooks, and cameras are becoming increasingly more important to our society.  How rarely we leave the house without our trusty iPhone or Blackberry!  These devices will continue to get cheaper and lighter, and will increasingly incorporate flexible components or displays. April 30, 2009 SAM meets Carboranes Self-assembled monolayer (SAM) structures and properties are dominated by two interactions: those between the substrate and adsorbate and those between the adsorbates themselves. April 30, 2009

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Mentor Enhancing Yield Diagnostics Tool

TOP STORY... May 6, 2009

Mentor Graphics is adding more powerful statistical analysis techniques to its yield diagnostics tool, Yield Assist. The diagnostics method combines the more-complex, compressed data available from logic testers with information from logic netlists and design layouts. The technique can narrow down problem areas on the die, and shorten the time required for failure analysis.
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2009 IITC to Consider Metals for 22 nm

TOP STORY... May 4, 2009

Researchers at the International Interconnect Technology Conference (IITC), planned for June 1-3 in Sapporo, Japan, will present new metallization and processing schemes for contacts, barrier layers, wetting agents and copper silicides. The Sapporo IITC meeting will feature studies of copper contacts, ruthenium nitride barriers and CVD ruthenium wetting agents, among others.
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NEWS FROM THE WORLD OF MATERIALS

Visit the Materials360^® Plus and the Materials News pages on the MRS Website for continually updated research news and features

Image in Focus

Clandestine Attraction of a Transparent Ceramic
The valence electron density of the hexagonal layered transparent conductor indium zinc oxide, calculated within density functional theory and visualized using VESTA. Additional color rendering was performed using Photoshop. 
[Submitted by Aron Walsh, National Renewable Energy Laboratory, Golden, Colorado, to theScience as Art competition at the 2008 MRS Fall Meeting]

[We invite you to submit your images to the Editor for possible inclusion in this feature]

Materials in Focus

Self-healing concrete for safer, more durable infrastructure
A recently developed concrete material can heal itself when it cracks. Self-healing is possible because the material is designed to bend and crack in narrow hairlines rather than break and split in wide gaps, as traditional concrete behaves. In the lab, self-healed specimens recovered most if not all of their original strength after researchers subjected them to a 3 percent tensile strain.

Bendy, twistable polymer could improve oil refining
A bendy polymer that can recognise and separate aromatic hydrocarbons from aliphatic mixtures has been developed. Researchers built the porous 3D polymer using a flexible 1D polymer made from metal units bound to salen ligands. The resulting structure bends and twists when its polymer chains stretch, triggered by guest molecules entering or leaving the structure.

Ferroelectric oxide formed directly on silicon
Researchers have been able to add ferroelectric capability to an oxide material used in common computer transistors. They took strontium titanate, a normally non-ferroelectric variant of the ferroelectric material , and deposited it on silicon in such a way that the silicon squeezed it into a ferroelectric state. They grew coherently strained strontium titanate (SrTiO₃) films via oxide molecular beam epitaxy in direct contact with silicon, with no interfacial silicon dioxide. They were able to observe ferroelectricity in these ultrathin SrTiO₃ layers by means of piezoresponse force microscopy.

Energy Focus

Potassium improves photochemical characteristics of titania nanotubes
A research team has discovered, serendipitously, that a residue of a process used to build arrays of titania nanotubes—a residue that wasn't even noticed before this—plays an important role in improving the performance of the nanotubes in solar cells that produce hydrogen gas from water. Their results indicate that by controlling the deposition of potassium on the surface of the nanotubes, they can achieve significant energy savings in a promising new alternate energy system. When the research team compared the performance of potassium-bearing nanotubes to similar arrays deliberately prepared without potassium, the former required only about one-third the electrical energy to produce the same amount of hydrogen as an equivalent array of potassium-free nanotubes.

Carbene catalyst converts carbon dioxide from air to methanol 
A novel reaction scheme has been developed by which CO₂ can be efficiently converted into methanol under very mild conditions. The reaction is based on an N-heterocyclic carbene catalyst and a silane as the reducing agent. The basic framework of an N-heterocyclic carbene is a five-membered ring made of two nitrogen and three carbon atoms. Instead of having the usual four bonds, one of these carbon atoms only has two. The two electrons left over in the form of a lone pair, which makes this species highly reactive—reactive enough to attack CO₂.

Nano Focus

Nano-mechanical sensors wired by photonics 
Researchers have demonstrated silicon-based nanocantilevers, smaller than the wavelength of light, that operate on photonic principles eliminating the need for electric transducers and expensive laser setups in nanoelectromechanical system (NEMS) devices. The new study demonstrates how NEMS can be improved by using integrated photonics to sense the cantilever motion. The system can detect deflections in the nano-cantilever sensors as small as 0.0001 Angstroms.

Universal transduction scheme using dielectric forces for NEMS
Chemical analysts today are expected to track down even single molecules. Researchers have now constructed a system of nanostrings made of non-conducting material, where each string can be electrically excited separately. Thousands of these strings can be produced on a small chip. One of the devices that could be created with this system is a highly sensitive "artificial nose" that detects various molecules – pollutants for example – individually.

A zippy route to nanoribbons
Two teams of researchers working independently have reported a new strategy for forming graphene nanoribbons, by longitudinally "unzipping" carbon nanotubes. Compared with other procedures for preparing graphene nanoribbons, which are narrow and elongated one-atom-thick strips of carbon, the new routes are simpler, less expensive, and potentially better suited to making bulk quantities of the material. The first team treated the nanotubes with sulfuric acid and potassium permanganate. The second team partially embedded the nanotubes in a polymer film to hold them in place and then etched them with an argon plasma.

Bio Focus

Spider silk toughness greatly increased by metal infiltration 
Researchers have used atomic-layer deposition to pulse zinc, titanium, and aluminum ions into spider silk. The resulting materials show greatly enhanced toughness over natural spider silk and could be used to make protective clothing or even new structural materials. The protein-metal composites are tougher than the sum of their parts.

AFM reveals hidden differences between normal and cancerous cells 
Using an atomic force microscope, researchers have identified an important difference in the surface properties of normal and cancerous cells. They found that normal cells have "brushes" of one length on their surface while cancerous cells have two brush lengths that have very different densities to the brushes on normal cells. This important variation means that cancer and normal cells may interact very differently with nanoparticles, something that could be exploited for cancer detection and treatment via drug delivery.

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Soitec Ready With Ultrathin SOI Wafers

David Lammers, News Editor -- Semiconductor International, 7/16/2008

Soitec has qualified silicon-on-insulator (SOI) wafers with ultrathin buried oxide (BOX) and silicon layers. The SOI wafers -- named XUT+ to describe the ultrathin top silicon and BOX layers -- are aimed at both partially depleted (PD) and fully depleted (FD) devices, including multi-gate transistor architectures, such as finFET and trigate, that may play a role at 22 nm and beyond. More

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Sp3 Diamond Revs SOD Wafer Production

Staff -- Semiconductor International, 4/14/2009

Sp3 Diamond Technologies Inc. is taking orders for 2 and 4 in. silicon-on-diamond (SOD) wafers for use in production of high-power ICs. The company is accelerating development of 6 in. wafers for use as laterally diffused metal oxide semiconductor (LDMOS) substrates. The SOD wafers, which have top layers of GaN compounds, deliver higher thermal conductivity at a lower cost than existing SiC alternatives to GaN. More

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Inlustra Starts Nonpolar GaN Production

David Lammers, News Editor -- Semiconductor International, 4/14/2009

Inlustra said it is beginning to deliver nonpolar GaN substrates to customers. Started in 2005 as a spin-out from UC Santa Barbara, the company says it has developed proprietary techniques to significantly reduce the number of defects in nonpolar GaN substrates, resulting in improved LED yields. The long-term demand for GaN materials is expected to be strong as GaN-based white LEDs used for general lighting begin to replace fluorescent and incandescent bulbs. More

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