Category Archives: Materials

They are among the thinnest structures on earth: “two dimensional materials” are crystals which consist of only one or a few layers of atoms. They often display unusual properties, promising many new applications in opto-electronics and energy technology. One of these materials is 2D-molybdenum sulphide, an atomically thin layer of molybdenum and sulphur atoms.

The production of such ultra-thin crystals is difficult. The crystallisation process depends on many different factors. In the past, different techniques have yielded quite diverse results, but the reasons for this could not be accurately explained. Thanks to a new method developed by research teams at TU Wien, the University of Vienna and Joanneum Research in Styria, for the first time ever it is now possible to observe the crystallisation process directly under the electron microscope. The method has now been presented in the scientific journal ACS Nano.

At first, the atoms are randomly distributed, after being manipulated with the electron beam, they form crystal structures (right). Credit: TU Wien

From gas to crystal

“Molybdenum sulphide can be used in transparent and flexible solar cells or for sustainably generating hydrogen for energy storage”, says the lead author of the study, Bernhard C. Bayer from the Institute of Materials Chemistry at TU Wien. “In order to do this, however, high-quality crystals must be grown under controlled conditions.”

Usually this is done by starting out with atoms in gaseous form and then condensing them on a surface in a random and unstructured way. In a second step, the atoms are arranged in regular crystal form – through heating, for example. “The diverse chemical reactions during the crystallisation process are, however, still unclear, which makes it very difficult to develop better production methods for 2D materials of this kind”, Bayer states.

Thanks to a new method, however, it should now be possible to accurately study the details of the crystallisation process. “This means it is no longer necessary to experiment through trial and error, but thanks to a deeper understanding of the processes, we can say for certain how to obtain the desired product”, Bayer adds.

Graphene as a substrate

First, molybdenum and sulphur are placed randomly on a membrane made of graphene. Graphene is probably the best known of the 2D materials – a crystal with a thickness of only one atom layer consisting of carbon atoms arranged in a honeycomb lattice. The randomly arranged molybdenum and sulphur atoms are then manipulated in the electron microscope with a fine electron beam. The same electron beam can be used simultaneously to image the process and to initiate the crystallization process.

That way it has now become possible for the first time to directly observe how the atoms move and rearrange during the growth of the material with a thickness of only two atomic layers. “In doing so, we can see that the most thermodynamically stable configuration doesn’t necessarily always have to be the final state”, Bayer says. Different crystal arrangements compete with one another, transform into each other and replace one another. “Therefore, it is now clear why earlier investigations had such varying results. We are dealing with a complex, dynamic process.” The new findings will help to adapt the structure of the 2D materials more precisely to application requirements in future by interfering with the rearrangement processes in a targeted manner.

Roger Carpenter, a Google hardware engineer with 30 years of experience in electronic design automation and chip design, has been elected to the Silicon Integration Initiative board of directors. Si2 is a research and development joint venture that provides standard interoperability solutions for integrated circuit design tools.

Before joining Google, Carpenter held executive roles at three EDA firms: Magma Design Automation, Javelin Design Automation and Envis. His design experience includes positions at Wave Computing, Broadcom, Chromatic Research and Xilinx. A holder of more than a dozen patents, Carpenter received a Bachelor’s and Master’s of Electrical Engineering and Computer Science from the Massachusetts Institute of Technology.

John Ellis, Si2 president and CEO, said that Google’s membership on the Si2 board reflects the increasing impact of vertical integration in the electronics industry.  “A recent Si2 industry survey showed that over 80 percent of our end users develop some specialized, internal design tools. This proprietary software meets their unique needs and performance requirements,” Ellis said.

“Directly accessing the Si2 OpenAccess data base by making use of our Application Programming Interface, designers and integrators have greater control over their bottom line by optimizing their design flow and, in turn, shortening product time-to-market. It’s critical that system houses like Google, along with their unique semiconductor design software needs, are now represented on the Si2 board.”

The twelve members of the Si2 board represent leading semiconductor manufacturers and foundries, fabless companies, and EDA software providers.

Scientists at Tokyo Institute of Technology designed a new type of molecular wire doped with organometallic ruthenium to achieve unprecedentedly higher conductance than earlier molecular wires. The origin of high conductance in these wires is fundamentally different from similar molecular devices and suggests a potential strategy for developing highly conducting “doped” molecular wires.

The proposed wire is ‘doped’ with a ruthenium unit that enhances its conductance to unprecedented levels compared with previously reported similar molecular wires. Credit: Journal of the American Chemical Society

Since their conception, researchers have tried to shrink electronic devices to unprecedented sizes, even to the point of fabricating them from a few molecules. Molecular wires are one of the building blocks of such minuscule contraptions, and many researchers have been developing strategies to synthesize highly conductive, stable wires from carefully designed molecules.

A team of researchers from Tokyo Institute of Technology, including Yuya Tanaka, designed a novel molecular wire in the form of a metal electrode-molecule-metal electrode (MMM) junction including a polyyne, an organic chain-like molecule, “doped” with a ruthenium-based unit Ru(dppe)2. The proposed design, featured in the cover of the Journal of the American Chemical Society, is based on engineering the energy levels of the conducting orbitals of the atoms of the wire, considering the characteristics of gold electrodes.

Using scanning tunneling microscopy, the team confirmed that the conductance of these molecular wires was equal to or higher than those of previously reported organic molecular wires, including similar wires “doped” with iron units. Motivated by these results, the researchers then went on to investigate the origin of the proposed wire’s superior conductance. They found that the observed conducting properties were fundamentally different from previously reported similar MMM junctions and were derived from orbital splitting. In other words, orbital splitting induces changes in the original electron orbitals of the atoms to define a new “hybrid” orbital facilitating electron transfer between the metal electrodes and the wire molecules. According to Tanaka, “such orbital splitting behavior has rarely been reported for any other MMM junction”.

Since a narrow gap between the highest (HOMO) and lowest (LUMO) occupied molecular orbitals is a crucial factor for enhancing conductance of molecular wires, the proposed synthesis protocol adopts a new technique to exploit this knowledge, as Tanaka adds “The present study reveals a new strategy to realize molecular wires with an extremely narrow HOMO?LUMO gap via MMM junction formation.”

This explanation for the fundamentally different conducting properties of the proposed wires facilitate the strategic development of novel molecular components, which could be the building blocks of future minuscule electronic devices.

TowerJazz, the global specialty foundry, today announced its participation at European Microwave Week (EuMW), being held in Madrid, Spain on September 25 – 27, 2018. The Company will showcase its extensive RF silicon process capability including its advanced SiGe and RF SOI technologies, addressing the emerging 5G and mmWave markets and focusing on high-data rate mobile and automotive applications.

TowerJazz will present its best-in-class, high volume SiGe BiCMOS technology for 5G mobile transmit-receive chips with greater than 12 Gbps data rates, with record performance at the 28GHz band, representing a more than 10-times improvement in data rate vs. 4G LTE, and meeting many other technical specification requirements of the emerging 5G standard. The Company will also highlight its 5G RF SOI technology which includes its newest 65nm process ramping on 300mm wafers with best-in-class LNA and switch performance to address integration in the front-end-module. The process can reduce losses in an RF switch improving battery life and boosting data rates in handsets and IoT terminals.

During the conference, TowerJazz will participate on a panel to discuss RF semiconductor solutions for 5G systems. The panel session is scheduled for September 25, 2018 from 11:00 a.m. until noon.

Global semiconductor industry revenue grew 4.4 percent, quarter over quarter, in the second quarter of 2018, reaching a record $120.8 billion. Semiconductor growth occurred in all application markets and world regions, according to IHS Markit (Nasdaq: INFO).

“The explosive growth in enterprise and storage drove the market to new heights in the second quarter,” said Ron Ellwanger, senior analyst and component landscape tool manager, IHS Markit. “This growth contributed to record application revenue in data processing and wired communication markets as well as in the microcomponent and memory categories.”

Due to the ongoing growth in the enterprise and storage markets, sequential microcomponent sales grew 6.5 percent in the second quarter, while memory semiconductor revenue increased 6.4 percent. “Broadcom Limited experienced exceptional growth in its wired communication division, due to increased cloud and data-center demand,” Ellwanger said.

Memory component revenue continued to rise in the second quarter, compared to the previous quarter, reaching $42.0 billion dollars. “This is the ninth consecutive quarter of rising revenue from memory components, and growth in the second quarter of 2018 was driven by higher density in enterprise and storage,” Ellwanger said. “This latest uptick comes at a time of softening prices for NAND flash memory. However, more attractive pricing for NAND memory is pushing SSD demand and revenue higher.”

Semiconductor market share

Samsung Electronics continued to lead the overall semiconductor industry in the second quarter with 15.9 percent of the market, followed by Intel at 13.9 percent and SK Hynix at 7.9 percent. Quarter-over-quarter market shares were relatively flat, with no change in the top-three ranking. SK Hynix achieved the highest growth rate and record quarterly sales among the top three companies, recording 16.4 percent growth in the second quarter.

A team of researchers led by the University of Minnesota has developed a new material that could potentially improve the efficiency of computer processing and memory. The researchers have filed a patent on the material with support from the Semiconductor Research Corporation, and people in the semiconductor industry have already requested samples of the material.

The findings are published in Nature Materials, a peer-reviewed scientific journal published by Nature Publishing Group.

This cross-sectional transmission electron microscope image shows a sample used for the charge-to-spin conversion experiment. The nano-sized grains of less than 6 nanometers in the sputtered topological insulator layer created new physical properties for the material that changed the behavior of the electrons in the material. Credit: Wang Group, University of Minnesota

“We used a quantum material that has attracted a lot of attention by the semiconductor industry in the past few years, but created it in unique way that resulted in a material with new physical and spin-electronic properties that could greatly improve computing and memory efficiency,” said lead researcher Jian-Ping Wang, a University of Minnesota Distinguished McKnight Professor and Robert F. Hartmann Chair in electrical engineering.

The new material is in a class of materials called “topological insulators,” which have been studied recently by physics and materials research communities and the semiconductor industry because of their unique spin-electronic transport and magnetic properties. Topological insulators are usually created using a single crystal growth process. Another common fabrication technique uses a process called Molecular Beam Epitaxy in which crystals are grown in a thin film. Both of these techniques cannot be easily scaled up for use in the semiconductor industry.

In this study, researchers started with bismuth selenide (Bi2Se3), a compound of bismuth and selenium. They then used a thin film deposition technique called “sputtering,” which is driven by the momentum exchange between the ions and atoms in the target materials due to collisions. While the sputtering technique is common in the semiconductor industry, this is the first time it has been used to create a topological insulator material that could be scaled up for semiconductor and magnetic industry applications.

However, the fact that the sputtering technique worked was not the most surprising part of the experiment. The nano-sized grains of less than 6 nanometers in the sputtered topological insulator layer created new physical properties for the material that changed the behavior of the electrons in the material. After testing the new material, the researchers found it to be 18 times more efficient in computing processing and memory compared to current materials.

“As the size of the grains decreased, we experienced what we call ‘quantum confinement’ in which the electrons in the material act differently giving us more control over the electron behavior,” said study co-author Tony Low, a University of Minnesota assistant professor of electrical and computer engineering.

Researchers studied the material using the University of Minnesota’s unique high-resolution transmission electron microscopy (TEM), a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image.

“Using our advanced aberration-corrected scanning TEM we managed to identify those nano-sized grains and their interfaces in the film,” said Andre Mkhoyan, a University of Minnesota associate professor of chemical engineering and materials science and electron microscopy expert.

Researchers say this is only the beginning and that this discovery could open the door to more advances in the semiconductor industry as well as related industries, such as magnetic random access memory (MRAM) technology.

“With the new physics of these materials could come many new applications,” said Mahendra DC (Dangi Chhetri), first author of the paper and a physics Ph.D. student in Professor Wang’s lab.

Wang agrees that this cutting-edge research could make a big impact.

“Using the sputtering process to fabricate a quantum material like a bismuth-selenide-based topological insulator is against the intuitive instincts of all researchers in the field and actually is not supported by any existing theory,” Wang said. “Four years ago, with a strong support from Semiconductor Research Corporation and the Defense Advanced Research Projects Agency, we started with a big idea to search for a practical pathway to grow and apply the topological insulator material for future computing and memory devices. Our surprising experimental discovery led to a new theory for topological insulator materials.

“Research is all about being patient and collaborating with team members. This time there was a big pay off,” Wang said.

Sanan Integrated Circuit Co., a pure-play compound semiconductor foundry, today announces its entry into the North American, European, and Asia Pacific (APAC) markets with their advanced III-V technology platform. With their broad portfolio of gallium arsenide (GaAs) HBT, pHEMT, BiHEMT, integrated passive device (IPD), filters, gallium nitride (GaN) power HEMT, silicon carbide (SiC), and indium phosphide (InP) DHBT process technologies, they cover a wide range of applications among today’s active microelectronics and photonics markets. Sanan IC is strongly focused on high performance, large scale, and high quality III-V semiconductor manufacturing and on serving the RF, millimeter wave, power electronics, and optical markets.

Founded in 2014, headquartered in Xiamen City, in the Fujian province of south China, Sanan IC is subsidiary of Sanan Optoelectronics Co., Ltd., the leading LED chip manufacturing company, based on GaN and GaAs technologies. Leveraging high volume production and years of investment in numerous epitaxial wafer reactors of its parent company for the LED lighting and solar photovoltaic markets, Sanan IC is expanding their go-to-market strategy beyond the Greater China region as their process technologies and patent portfolio mature, with a vision to fulfill the needs of independent design manufacturers (IDM’s) and fabless design houses for high volume compound semiconductor fabrication.

“We see tremendous opportunity in serving the world-wide demand for large scale production of 6-inch III-V epitaxial wafers, driven by continual growth of the RF, millimeter wave, power electronics, and optical markets,” said Raymond Cai, Chief Executive Officer of Sanan IC. “Our vertically integrated manufacturing services over our broad compound semiconductor technology platform, with in-house epitaxy and substrate capabilities, make us an ideal foundry partner. Given the capital investments made on state-of-the art equipment and facilities, with full support from our parent company, Sanan Optoelectronics, combined with strategic partnerships, and a world-class team of scientists and technologists, Sanan IC is well positioned for success in this active compound semiconductor market”.

As cellular mobility and wireless connectivity proliferates in the Internet-of-Things (IoT), and 5G sub-6GHz evolves into millimeter wave, III-V technologies become even more critical to support the infrastructure and client device deployments by carriers worldwide. According to Yole Développement (Yole), a leading technology market research firm, part of Yole Group of Companies, the GaAs wafer market, comprised of RF, photonics, photovoltaics, and LEDs, is expected to grow to over 4 million units in 2023, with photonics having the highest growth at 37% CAGR1. GaN and SiC for power electronics, such as for data centers, electric vehicles (EVs), battery chargers, power supplies, LiDAR, and audio, are predicted to ramp up, with GaN reaching up to $460M shipments by 2022 with a CAGR of 79%2 while SiC projects to reach $1.4B at 29% CAGR by 20233. Optical components continue to be in high demand for datacom, telecom, consumer, automotive and industrial markets, leading to increased revenues for photodectors, laser diodes, and especially VCSELs with expected shipments of $3.5B in 20234. As these applications emerge, Sanan IC is poised to support the industry’s needs.

Sources:
1GaAs Wafer & Epiwafer Market: RF, Photonics, LED & PV Applications Report, Yole Développement (Yole), 2018
2,3Power SiC 2018: Materials, Devices and Applications Report, Yole Développement (Yole), 2018
4Source: VCSELs – Technology, Industry & Market Trends report, Yole Développement (Yole), 2018

TowerJazz, the global specialty foundry, today announced its participation at the 44th European Conference on Optical Communication (ECOC) being held in Rome, Italy on September 23-27, 2018. The Company will showcase its advanced SiGe (Silicon Germanium) process, with speeds in excess of 300GHz, and its newest production SiPho (Silicon Photonics) process built into data center high-speed optical data links.

TowerJazz has a significant foundry share of the 100Gb/s transceiver market served by its SiGe Terabit Platform and will showcase even higher SiGe transistor speeds and patented features appropriate for 200 and 400Gb/s communication ICs such as  transimpedance amplifiers (TIAs), laser and modulator drivers, and clock and data recovery circuits.

TowerJazz’s SiPho production platform enables high bandwidth photo diodes, together with waveguides and modulators, with a roadmap to allow InP components on the same die and permit a high-level of optical integration for next-generation data center optical links.  An open design kit is available to all customers and supported by prototyping and shuttle runs.

To set up a meeting or see a demo with TowerJazz technical experts at the TowerJazz ECOC booth (#569), or for more information, please click here or inquire at: [email protected].

A Princeton-led study has revealed an emergent electronic behavior on the surface of bismuth crystals that could lead to insights on the growing area of technology known as “valleytronics.”

The term refers to energy valleys that form in crystals and that can trap single electrons. These valleys potentially could be used to store information, greatly enhancing what is capable with modern electronic devices.

In the new study, researchers observed that electrons in bismuth prefer to crowd into one valley rather than distributing equally into the six available valleys. This behavior creates a type of electricity called ferroelectricity, which involves the separation of positive and negative charges onto opposite sides of a material. This study was made available online in May 2018 and published this month in Nature Physics.

The finding confirms a recent prediction that ferroelectricity arises naturally on the surface of bismuth when electrons collect in a single valley. These valleys are not literal pits in the crystal but rather are like pockets of low energy where electrons prefer to rest.

The researchers detected the electrons congregating in the valley using a technique called scanning tunneling microscopy, which involves moving an extremely fine needle back and forth across the surface of the crystal. They did this at temperatures hovering close to absolute zero and under a very strong magnetic field, up to 300,000 times greater than Earth’s magnetic field.

The behavior of these electrons is one that could be exploited in future technologies. Crystals consist of highly ordered, repeating units of atoms, and with this order comes precise electronic behaviors. Silicon’s electronic behaviors have driven modern advances in technology, but to extend our capabilities, researchers are exploring new materials. Valleytronics attempts to manipulate electrons to occupy certain energy pockets over others.

The existence of six valleys in bismuth raises the possibility of distributing information in six different states, where the presence or absence of an electron can be used to represent information. The finding that electrons prefer to cluster in a single valley is an example of “emergent behavior” in that the electrons act together to allow new behaviors to emerge that wouldn’t otherwise occur, according to Mallika Randeria, the first author on the study and a graduate student at Princeton working in the laboratory of Ali Yazdani, the Class of 1909 Professor of Physics.

“The idea that you can have behavior that emerges because of interactions between electrons is something that is very fundamental in physics,” Randeria said. Other examples of interaction-driven emergent behavior include superconductivity and magnetism.

If you’re ever unlucky enough to have a car with metal tires, you might consider a set made from a new alloy engineered at Sandia National Laboratories. You could skid — not drive, skid — around the Earth’s equator 500 times before wearing out the tread.

Sandia’s materials science team has engineered a platinum-gold alloy believed to be the most wear-resistant metal in the world. It’s 100 times more durable than high-strength steel, making it the first alloy, or combination of metals, in the same class as diamond and sapphire, nature’s most wear-resistant materials. Sandia’s team recently reported their findings in Advanced Materials. “We showed there’s a fundamental change you can make to some alloys that will impart this tremendous increase in performance over a broad range of real, practical metals,” said materials scientist Nic Argibay, an author on the paper.

Although metals are typically thought of as strong, when they repeatedly rub against other metals, like in an engine, they wear down, deform and corrode unless they have a protective barrier, like additives in motor oil.

In electronics, moving metal-to-metal contacts receive similar protections with outer layers of gold or other precious metal alloys. But these coatings are expensive. And eventually they wear out, too, as connections press and slide across each other day after day, year after year, sometimes millions, even billions of times. These effects are exacerbated the smaller the connections are, because the less material you start with, the less wear and tear a connection can endure before it no longer works.

With Sandia’s platinum-gold coating, only a single layer of atoms would be lost after a mile of skidding on the hypothetical tires. The ultradurable coating could save the electronics industry more than $100 million a year in materials alone, Argibay says, and make electronics of all sizes and across many industries more cost-effective, long-lasting and dependable — from aerospace systems and wind turbines to microelectronics for cell phones and radar systems.

“These wear-resistant materials could potentially provide reliability benefits for a range of devices we have explored,” said Chris Nordquist, a Sandia engineer not involved in the study. “The opportunities for integration and improvement would be device-specific, but this material would provide another tool for addressing current reliability limitations of metal microelectronic components.”

New metal puts an old theory to rest

You might be wondering how metallurgists for thousands of years somehow missed this. In truth, the combination of 90 percent platinum with 10 percent gold isn’t new at all.

But the engineering is new. Argibay and coauthor Michael Chandross masterminded the design and the new 21st century wisdom behind it. Conventional wisdom says a metal’s ability to withstand friction is based on how hard it is. The Sandia team proposed a new theory that says wear is related to how metals react to heat, not their hardness, and they handpicked metals, proportions and a fabrication process that could prove their theory.

“Many traditional alloys were developed to increase the strength of a material by reducing grain size,” said John Curry, a postdoctoral appointee at Sandia and first author on the paper. “Even still, in the presence of extreme stresses and temperatures many alloys will coarsen or soften, especially under fatigue. We saw that with our platinum-gold alloy the mechanical and thermal stability is excellent, and we did not see much change to the microstructure over immensely long periods of cyclic stress during sliding.”

Now they have proof they can hold in their hands. It looks and feels like ordinary platinum, silver-white and a little heavier than pure gold. Most important, it’s no harder than other platinum-gold alloys, but it’s much better at resisting heat and a hundred times more wear resistant.

The team’s approach is a modern one that depended on computational tools. Argibay and Chandross’ theory arose from simulations that calculated how individual atoms were affecting the large-scale properties of a material, a connection that’s rarely obvious from observations alone. Researchers in many scientific fields use computational tools to take much of the guesswork out of research and development.

“We’re getting down to fundamental atomic mechanisms and microstructure and tying all these things together to understand why you get good performance or why you get bad performance, and then engineering an alloy that gives you good performance,” Chandross said.

A slick surprise

Still, there will always be surprises in science. In a separate paper published in Carbon, the Sandia team describes the results of a remarkable accident. One day, while measuring wear on their platinum-gold, an unexpected black film started forming on top. They recognized it: diamond-like carbon, one of the world’s best man-made coatings, slick as graphite and hard as diamond. Their creation was making its own lubricant, and a good one at that.

Diamond-like carbon usually requires special conditions to manufacture, and yet the alloy synthesized it spontaneously.

“We believe the stability and inherent resistance to wear allows carbon-containing molecules from the environment to stick and degrade during sliding to ultimately form diamond-like carbon,” Curry said. “Industry has other methods of doing this, but they typically involve vacuum chambers with high temperature plasmas of carbon species. It can get very expensive.”

The phenomenon could be harnessed to further enhance the already impressive performance of the metal, and it could also potentially lead to a simpler, more cost-effective way to mass-produce premium lubricant.