Terahertz integration platforms using substrateless all-silicon microstructures

Abstract

The absence of a suitable standard device platform for terahertz waves is currently a major roadblock that is inhibiting the widespread adoption and exploitation of terahertz technology. As a consequence, terahertz-range devices and systems are generally an ad hoc combination of several different heterogeneous technologies and fields of study, which serves perfectly well for a once-off experimental demonstration or proof-of-concept, but is not readily adapted to real-world use case scenarios. In contrast, establishing a common platform would allow us to consolidate our design efforts, define a well-defined scope of specialization for “terahertz engineering,” and to finally move beyond the disconnected efforts that have characterized the past decades. This tutorial will present arguments that nominate substrateless all-silicon microstructures as the most promising candidate due to the low loss of high-resistivity float-zone intrinsic silicon, the compactness of high-contrast dielectric waveguides, the designability of lattice structures, such as effective medium and photonic crystal, physical rigidity, ease and low cost of manufacture using deep-reactive ion etching, and the versatility of the many diverse functional devices and systems that may be integrated. We will present an overview of the historical development of the various constituents of this technology, compare and contrast different approaches in detail, and briefly describe relevant aspects of electromagnetic theory, which we hope will be of assistance.

Phase-Controllable Spoof Surface Plasmon Coupling From Bull's Eye Aperture to Planar Silicon Waveguide in the Terahertz Band

“…The fabrication of the proposed device is based on silicon micromachining, which is suitable for the collective fabrication of a large number of elements required for future mobile devices. It is also compatible with silicon-based elements for steering terahertz waves [18][19][20][21]66]. Structures that can be formed using silicon micromachining have dimensions comparable to the wavelengths of terahertz waves, 30 µm to 3000 µm, and are believed to be necessary to develop a wide variety of devices to realize Beyond 5G/6G.…”

“…Therefore, even microstrip lines and coplanar lines conventionally used in the millimeter wave band are considered difficult to apply in the terahertz band [14]. Moreover, dielectric waveguides that confine the electromagnetic field within a dielectric material with lower absorption such as dielectric image lines, non-radiative dielectric waveguides, and silicon waveguides are desirable [15][16][17][18][19][20]. The antenna could also be constructed from a lowloss dielectric material instead of metal [21].…”