(Keynote) Terahertz Nanoplasmonics Technology: Physics, Applications, and Commercialization

Abstract

The minimum feature sizes of the Si VLSI reduced to 7 nm in 2017 with the 5 nm Si VLSI reported at IEDM 2019 and 3 nm Si VLSI technology on the roadmap for 2021. These transistors operate in the regime when the electron mean free path for collisions with impurities or lattice vibrations exceeds the device dimension. One new feature of this mode of transport is “ballistic mobility” replacing the conventional mobility and being proportional to the channel length. At high frequencies, the electron inertia in short channel devices plays a dominant role and the waves of the electron density (plasma waves) enable the device response well into the terahertz (THz) range of frequencies. Excitation and rectification of the plasma waves enables numerous application in terahertz sensing and communications. Terahertz sensing enables detection of biological and chemical hazardous agents, cancer detection, detection of mines and explosives, provides security in buildings, airports, and other public spaces, and widely used for industry quality control and radio astronomy applications. A new emerging application is for cyber hardware security to distinguish between faked and genuine VLSI chips and predict the VLSI reliability. THz communications, extensively explored since the beginning of the 21-st century, will enable very high data rates (over 430 GPS demonstrated for the W-band) for applications such as driverless cars, autonomous tactical networking with ground and aerial vehicles, and 4K video and cloud storage applications. THz signals can penetrate through fog and dust. The available bandwidth at THz frequencies, makes them uniquely suited for Wireless Local Area Networks (WLAN) and Wireless Personal Area Networks (WPAN). THz sources and detectors can produce tight beam widths and support low power directional networking. The 200 to 300 GHz band is proposed for the next generation Wi-Fi (beyond 5G) that could be implemented using deep submicron silicon. GaN, p-diamond, and graphene based Terahertz FETs – TeraFETs - will compete with Si for THz applications promising further improvements in THz detectivity and generated THz power. There is, however, a large gap between the advanced experimental and theoretical THz electronics research and currently deployed THz technology. I will discuss the problems facing the THz plasmonic nanoplasmonics technology commercialization and projections for bridging the famous THz gap. Figure 1