semiconductor technology (8)

When Water Outpaces Silicon…

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On target: Water is fanned out through a specially developed nozzle, and then a laser pulse is passed through it to create a switch. (Courtesy: Adrian Buchmann)

Topics: Applied Physics, Lasers, Materials Science, Photonics, Semiconductor Technology

A laser-controlled water-based switch that operates twice as fast as existing semiconductor switches has been developed by a trio of physicists in Germany. Adrian Buchmann, Claudius Hoberg, and Fabio Novelli at Ruhr University Bochum used an ultrashort laser pulse to create a temporary metal-like state in a jet of liquid water. This altered the transmission of terahertz pulses over timescales of just tens of femtoseconds.

With the latest semiconductor-based switches approaching fundamental upper limits on how fast they can operate, researchers are searching for faster ways of switching signals. One unexpected place to look for inspiration is the curious behavior of water under extreme conditions – like those deep within ice-giant planets or created by powerful lasers.

Molecular dynamics simulations suggest water enters a metallic state at pressures of 300 GPa and temperatures of 7000 K. While such conditions do not occur on Earth, it is possible that this state contributes to the magnetic fields of Uranus and Neptune. To study this effect closer to home, recent experiments have used powerful, ultrashort laser pulses to trigger photo-ionization in water-based solutions – creating fleeting, metal-like states.

Water-based switch outpaces semiconductor devices, described in APL Photonics.

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Chip Act and Wave Surfing...

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Massive subsidies to regain the edge of the US semiconductor industry will not likely succeed unless progress is made in winning the global race of idea flow and monetization.

Topics: Applied Physics, Chemistry, Computer Science, Electrical Engineering, Semiconductor Technology

Intelligent use of subsidies for winning the global idea race is a must for gaining and regaining semiconductor edge.

The US semiconductor industry started with the invention of Bell Labs. Subsequently, it attained supremacy in semiconductor production due to the success of making computers better and cheaper. Notably, the rise of the PC wave made Intel and Silicon Valley seemingly unsinkable technology superpowers. But during the first two decades of the 21st century, America has lost it. The USA now relies on Asia to import the most advanced chips. Its iconic Intel is now a couple of technology generation behind Asia’s TSMC and Samsung.

Furthermore, China’s aggressive move has added momentum to America’s despair, triggering a chip war. But why has America lost the edge? Why does it rely on TSMC and Samsung to supply the most advanced chips to power iPhones, Data centers, and Weapons? Is it due to Asian Governments’ subsidies? Or is it due to America’s failure to understand dynamics, make prudent decisions and manage technology and innovation?

Invention and rise and fall of US semiconductor supremacy

In 1947, Bell Labs of the USA invented a semiconductor device—the Transistor. Although American companies developed prototypes of Transistor radios and other consumer electronic products, they did not immediately pursue them. But American firms were very fast in using the Transistor to reinvent computers—by changing the vacuum tube technology core. Due to weight advantage, US Airforce and NASA found transistors suitable for onboard computers. Besides, the invention of integrated circuits by Fairchild and Texas instruments accelerated the weight and size reduction of digital logic circuits. Consequentially, the use of semiconductors in building onboard computers kept exponentially growing. Hence, by the end of the 1960s, the US had become a powerhouse in logic circuit semiconductors. But America remained 2nd to Japan in global production, as Japanese companies were winning the race of consumer electronics by using transistors.

US Semiconductor–from invention, supremacy to despair, Rokon Zaman, The-Waves.org

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Pushing Beyond Moore...

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Clean-room technicians at the AIM Photonics NanoTech chip fabrication facility in Albany, New York.  Credit: SUNY Polytechnic Institute

Topics: Computer Science, Electrical Engineering, Materials Science, Nanotechnology, Semiconductor Technology

Over 50 Years of Moore's Law - Intel

GAITHERSBURG, Md. — The U.S. Department of Commerce’s National Institute of Standards and Technology (NIST) has entered into a cooperative research and development agreement with AIM Photonics that will give chip developers a critical new tool for designing faster chips that use both optical and electrical signals to transmit information. Called integrated photonic circuits, these chips are key components in fiber-optic networks and high-performance computing facilities. They are used in laser-guided missiles, medical sensors, and other advanced technologies. 

AIM Photonics, a Manufacturing USA institute, is a public-private partnership that accelerates the commercialization of new technologies for manufacturing photonic chips. The New York-based institute provides small and medium-sized businesses, academics, and government researchers access to expertise and fabrication facilities during all phases of the photonics development cycle, from design to fabrication and packaging.

NIST and AIM Photonics Team Up on High-Frequency Optical/Electronic Chips

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Thermo Limits

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A radical reimagining of information processing could greatly reduce the energy use—as well as greenhouse gas emissions and waste heat—from computers. Credit: vchal/Getty Images

Topics: Climate Change, Computer Science, Electrical Engineering, Global Warming, Semiconductor Technology, Thermodynamics

In case you had not noticed, computers are hot—literally. A laptop can pump out thigh-baking heat, while data centers consume an estimated 200 terawatt-hours each year—comparable to the energy consumption of some medium-sized countries. The carbon footprint of information and communication technologies as a whole is close to that of fuel used in the aviation industry. And as computer circuitry gets ever smaller and more densely packed, it becomes more prone to melting from the energy it dissipates as heat.

Now physicist James Crutchfield of the University of California, Davis, and his graduate student Kyle Ray have proposed a new way to carry out computation that would dissipate only a small fraction of the heat produced by conventional circuits. In fact, their approach, described in a recent preprint paper, could bring heat dissipation below even the theoretical minimum that the laws of physics impose on today’s computers. That could greatly reduce the energy needed to both perform computations and keep circuitry cool. And it could all be done, the researchers say, using microelectronic devices that already exist.

In 1961 physicist Rolf Landauer of IBM’s Thomas J. Watson Research Center in Yorktown Heights, N.Y., showed that conventional computing incurs an unavoidable cost in energy dissipation—basically, in the generation of heat and entropy. That is because a conventional computer has to sometimes erase bits of information in its memory circuits in order to make space for more. Each time a single bit (with the value 1 or 0) is reset, a certain minimum amount of energy is dissipated—which Ray and Crutchfield have christened “the Landauer.” Its value depends on ambient temperature: in your living room, one Landauer would be around 10–21 joule. (For comparison, a lit candle emits on the order of 10 joules of energy per second.)

‘Momentum Computing’ Pushes Technology’s Thermodynamic Limits, Phillip Ball, Scientific American

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Cooling Computer Chips...

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An electron microscopy image of a gallium nitride-boron arsenide heterostructure interface at atomic resolution. Courtesy: The H-Lab/UCLA

Topics: Materials Science, Nanotechnology, Semiconductor Technology

A novel semiconducting material with high thermal conductivity can be integrated into high-power computer chips to cool them down and so improve their performance. The material, boron arsenide, is better at removing heat than the best thermal-management devices available today, according to the US-based researchers who developed it.

The size of computer chips has been shrinking over the years and has now reached the nanoscale, meaning that billions of transistors can be squeezed onto a single computer chip. This increased density of chips has enabled faster, more powerful computers, but it also generates localized hot spots on the chips. If this extra heat is not dealt with properly during operation, computer processors begin to overheat. This slows them down and makes them inefficient.

Defect-free boron arsenide

Researchers led by Yongjie Hu at the University of California, Los Angeles, recently developed a new thermal-management material that is much more efficient at drawing out and dissipating heat than other known metals or semiconducting materials such as diamond and silicon carbide. This new material is known as defect-free boron arsenide (BAs), and Hu and colleagues have now succeeded in interfacing it with computer chips containing wide-bandgap high-electron-mobility gallium nitride (GaN) transistors for the first time.

Using thermal transport measurements, the researchers found that processors interfaced with BAs and running at near maximum capacity had much lower hot-spot temperatures than other heat-management materials at the same transistor power density. During the experiment, the temperature of the BAs-containing devices increased from room temperature to roughly 360 K, compared to around 410 K and 440 K, respectively, for diamond and silicon carbide.

New semiconductor cools computer chips, Isabelle Dumé, Physics World

 

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Stop-Motion Efficiency...

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A team of researchers created a new method to capture ultrafast atomic motions inside the tiny switches that control the flow of current in electronic circuits. Pictured here are Aditya Sood (left) and Aaron Lindenberg (right). Courtesy: Greg Stewart/SLAC National Accelerator Laboratory

Topics: Applied Physics, Electrical Engineering, Nanotechnology, Semiconductor Technology

A new ultrafast imaging technique that captures the motion of atoms in nanoscale electronic devices has revealed the existence of a short-lived electronic state that could make it possible to develop faster and more energy-efficient computers. The imaging technique, which involves switching the devices on and off while taking snapshots of them with an electron diffraction camera, could also help researchers probe the limits of electronic switching.

“In general, we know very little about the intermediate phases materials pass through during electronic switching operations,” explains Aditya Sood, a postdoctoral researcher at the US Department of Energy’s SLAC National Accelerator Laboratory and lead author of a paper in Science about the new method. “Our technique allows for a new way to visualize this process and therefore address what is arguably one of the most important questions at the heart of computing – that is, what are the fundamental limits of electronic switches in terms of speed and energy consumption?”

Ultrafast electron diffraction camera

Sood and colleagues at SLACStanford UniversityHewlett Packard LabsPennsylvania State University, and Purdue University chose to study devices made from vanadium dioxide (VO2) because the material is known to transition between insulating and electrically conducting states near room temperature. It thus shows promise as a switch, but the exact pathway underlying electric field-induced switching in VOhas long been a mystery, Sood tells Physics World.

To take snapshots of VO2’s atomic structure, the team used periodic voltage pulses to switch an electronic device made from the material on and off. The researchers synchronized the timing of these voltage pulses with the high-energy electron pulses produced by SLAC’s ultrafast electron diffraction (UED) camera. “Each time a voltage pulse excited the sample, it was followed by an electron pulse with a delay that we could tune,” Sood explains. “By repeating this process many times and changing the delay each time, we created a stop-motion movie of the atoms moving in response to the voltage pulse.”

This is the first time that anyone has used UED, which detects tiny atomic movements in a material by scattering a high-energy beam of electrons off a sample, to observe an electronic device during operation. “We started thinking about this subject three years ago and soon realized that existing techniques were simply not fast enough,” says Aaron Lindenberg, a professor of materials science and engineering at Stanford and the study’s senior author. “So we decided to construct our own.”

‘Stop-motion movie of atoms’ reveals short-lived state in nanoscale switch, Isabelle Dumé, Physics World

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Integrated Nanodiamonds...

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Nanophotonic integration for simultaneously controlling a large number of quantum mechanical spins in nanodiamonds. (Image: P. Schrinner/AG Schuck)

Topics: Nanotechnology, Quantum Computer, Quantum Mechanics, Semiconductor Technology

(Nanowerk News) Physicists at Münster University have succeeded in fully integrating nanodiamonds into nanophotonic circuits and at the same time addressing several of these nanodiamonds optically. The study creates the basis for future applications in the field of quantum sensing schemes or quantum information processors.

The results have been published in the journal Nano Letters ("Integration of Diamond-Based Quantum Emitters with Nanophotonic Circuits").

Using modern nanotechnology, it is possible nowadays to produce structures that have feature sizes of just a few nanometers.

This world of the most minute particles – also known as quantum systems – makes possible a wide range of technological applications, in fields which include magnetic field sensing, information processing, secure communication, or ultra-precise timekeeping. The production of these microscopically small structures has progressed so far that they reach dimensions below the wavelength of light.

In this way, it is possible to break down hitherto existent boundaries in optics and utilize the quantum properties of light. In other words, nanophotonics represents a novel approach to quantum technologies.

Controlling fully integrated nanodiamonds, Westfälische Wilhelms-Universität Münster

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Diamond Nanoneedles...

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Credit: Z. Shi et al., Proc. Natl. Acad. Sci. USA 117, 24634 (2020)

Topics: Materials Science, Modern Physics, Nanotechnology, Semiconductor Technology

If you ever manage to deform a diamond, you’re likely to break it. That’s because the hardest natural material on Earth is also inelastic and brittle. Two years ago, Ming Dao (MIT), Subra Suresh (Nanyang Technological University in Singapore), and their collaborators demonstrated that when bulk diamonds are etched into fine, 300-nm-wide needles, they become nearly defect-free. The transformation allows diamonds to elastically bend under the pressure of an indenter tip, as shown in the figure, and withstand extremely large tensile stresses without breaking.

The achievement prompted the researchers to investigate whether the simple process of bending could controllably and reversibly alter the electronic structure of nanocrystal diamond. Teaming up with Ju Li and graduate student Zhe Shi (both at MIT), Dao and Suresh have now followed their earlier study with numerical simulations of the reversible deformation. The team used advanced deep-learning algorithms that reveal the bandgap distributions in nanosized diamond across a range of loading conditions and crystal geometries. The new work confirms that the elastic strain can alter the material’s carbon-bonding configuration enough to close its bandgap from a normally 5.6 eV width as an electrical insulator to 0 eV as a conducting metal. That metallization occurred on the compression side of a bent diamond nanoneedle.

Diamond nanoneedles turn metallic, R. Mark Wilson, Physics Today

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