The Silicon-Based XOI Wafer: The Most General Electronics-Photonics Platform for Computing, Sensing, and Communications

This paper proposes that the 300-mm-diameter silicon wafer coated with a thin insulator layer, which becomes a buried layer, is the most general and most capable platform for high-volume foundry-manufactured, waveguided, photonic integrated circuits (PICs) and for the on-wafer electronics that control and signal-process the photonics. We call this “on insulator” platform an electronic- photonic (or optoelectronic) integrated-circuit wafer. For a few potential applications like “general intelligence” (Shainline et al., 2021), entire wafers would be deployed. However, in almost every case, the wafer will be diced into hundreds of electronic-photonic chips (chips are the real aim of wafer creation). Those chips would be commercial products or custom-made, application-specific PICs. The goal of this paper is to present a detailed vision of the ultimate electronic- photonic wafers that: (1) serve a vast range of applications, (2) operate at any wavelength within the ultraviolet, visible, near-infrared and middle infrared, (3) provide low-loss, well-confined optical waveguiding across the wafer, (4) utilize an optimized or application-specific combination of photonic materials including semiconductors, insulators, ferroelectrics, poled polymers (Xu et al., 2022), phase-change materials (PCMs) (Wuttig et al., 2017), plasmonics (Moor et al., 2021), (Amin et al., 2021), and 2D materials such as graphene (Liu et al., 2020), (5) offer one-or-more practical electro-optical modulation-and-switching mechanisms that are discussed below, (6) offer on-wafer laser diodes, wavelength-multiplexed comb sources, LEDs, optical amplifiers, and photodetectors, (7) provide a full range of CMOS-or-“other” control electronics as well as electronic memories and data converters (analog-to-digital and digital-to-analog), and (8) are manufacturable in volume by proven techniques such as wafer bonding, smart cut, and hetero-epitaxy– or are made by emerging methods. The insulator mentioned above could be silicon dioxide (SiO2) or alumina (Al2O3), or silicon nitride (Si3N4 or SiN). SiO2 is generally preferred, but the Al2O3 and the SiN offer better mid- infrared transparency than the oxide.