There are scientific breakthroughs every day, almost all of which simply pass us by because our world is complex and nobody can absorb the movement of science and its implications on what we do every day. One of my ventures, which involves the use of superfine copper powder in the semi-conductor industry, just became a lot more interesting.
Yes, I do involve myself in some esoteric things from time to time and while the introduction of copper photonics in integrated circuits may not interest you, you will be using these in the near future. Is it a “better mousetrap”? I hope so.
Journal Reference:Dmitry Yu. Fedyanin, Dmitry I. Yakubovsky, Roman V. Kirtaev, Valentyn S. Volkov. Ultralow-Loss CMOS Copper Plasmonic Waveguides. Nano Letters, 2016; 16 (1): 362 DOI: 10.1021/acs.nanolett.5b03942
And before you flash NERD ALERT and move on to a discussion of Hillary’s cankles or something equally as interesting, consider that the next big thing in integrated circuits involves using light/photons to transmit information within the chip instead (nanophotonics) of electrons. These chips are used in increasingly small devices that are part of almost everything we touch.
The discovery made by researchers from the Moscow Institute of Physics and Technology (MIPT) will be used to replace existing components in data processing devices with more modern components by using photons instead of electrons.
Discussion of Plasmonics
While the main component in modern electronics, the transistor, can be scaled down in size to a few nanometres, the diffraction of light limits the minimum dimensions of photonic components to the size of about the light wavelength (~1 micrometre). Despite the fundamental nature of this so-called diffraction limit, one can overcome it by using metal-dielectric structures to create truly nanoscale photonic components. Most metals show a negative permittivity at optical frequencies, and light cannot propagate through them, penetrating to a depth of only 25 nanometres. Light may be converted into surface plasmon polaritons, surface waves propagating along the surface of a metal. This makes it possible to switch from conventional 3D photonics to 2D surface plasmon photonics, which is known as plasmonics. This gives a possibility to control light at the scale of the order of 100 nanometres, i.e. far beyond the diffraction limit.
It was previously believed that only two metals — gold and silver — could be used to build efficient nanophotonic metal-dielectric nanostructures and it was also thought that all other metals could not be an alternative to these two materials, since they exhibit strong absorption. However, in practice, creating components using gold and silver is not possible because both metals, as they are noble, do not enter into chemical reactions and therefore it is extremely difficult, expensive and in many cases simply impossible to use them to create nanostructures — the basis of modern photonics.
Unlike gold, copper can be easily structured using wet or dry etching. This gives a possibility to make nanoscale components that are easily integrated into silicon photonic or electronic integrated circuits. They succeeded in fabricating copper chips with optical properties that are not inferior to gold-based chips in a fabrication process compatible with the CMOS technology, which is the basis for all modern integrated circuits, including microprocessors.
These studies provide a foundation for the practical use of copper nanophotonic and plasmonic components, which in the very near future will be used to create LEDs, nanolasers, highly sensitive sensors and transducers for mobile devices, and high performance optoelectronic processors with several tens of thousand cores for graphics cards, personal computers, and supercomputers.