Made from indium phosphide and indium gallium arsenide, "the new transistor utilizes a pseudomorphic grading of the base and collector regions," said Milton Feng, the Holonyak Chair Professor of Electrical and Computer Engineering at Illinois. "The compositional grading of these components enhances the electron velocity, hence, reduces both current density and charging time."
With their latest device, Feng and his research group have taken the transistor to a new range of high-speed operation, bringing the "Holy Grail" of a terahertz transistor finally within reach. Faster transistors translate into faster computers, more flexible and secure wireless communications systems, and more effective combat systems.
In addition to using pseudomorphic material construction, the researchers also refined their fabrication process to produce tinier transistor components. For example, the transistor’s base is only 12.5 nanometers thick (a nanometer is one billionth of a meter, or about 10,000 times smaller than the width of a human hair).
"By scaling the device vertically, we have reduced the distance electrons have to travel, resulting in an increase in transistor speed," said graduate student William Snodgrass, who will describe the new device at the International Electronics Device Meeting in San Francisco, Dec. 11-13. "Because the size of the collector has also been reduced laterally, the transistor can charge and discharge faster."
Operated at room temperature (25 degrees Celsius), the transistor speed is 765 gigahertz. Chilled to minus 55 degrees Celsius, the speed increases to 845 gigahertz.
Feng, Snodgrass and graduate student Walid Hafez (now at Intel Corp.) fabricated the high-speed device in the university’s Micro and Nanotechnology Laboratory.
In addition to further increasing the transistor speed, Feng wants to reduce the current density even more, which will reduce junction temperature and improve device reliability.
James E. Kloeppel | EurekAlert!
Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent
25.09.2017 | Fraunhofer-Institut für Solare Energiesysteme ISE
Producing electricity during flight
20.09.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
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