Silicon-Based Integration Technology for Terahertz Systems
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Date
2023-09-20
Authors
Bassiouny, Amr
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Low-loss integration technologies are essential for the design of high-frequency systems
and components. Conventional PCB methods, such as metallic transmission lines, become
challenging to employ in the Terahertz (THz) region due to significant ohmic and
radiation losses. This thesis aims to design, fabricate, and test THz systems using a
promising all-silicon multi-band integration technology: Effective Medium-Suspended Silicon
Waveguide (EM-SSW). The technology utilizes high-resistivity silicon (HR-Si) and
photonic crystal-like effective medium structures to construct waveguides with high-modal
confinement. Additionally, suspending the waveguide’s core minimizes substrate-modal
interaction, enabling multi-band high-performance up to the THz range. To assess the
practical performance of the proposed technology, our research investigates two systems:
D-band and Y-band frequency up-converted sources. These devices are implemented using
cascaded tripler blocks that leverage the non-linearity of GaAs Schottky diode chips
to generate harmonic output power. The chips are mounted on the silicon wafer using
an embedded-chip ultra-short wire bonding packaging technique within the high-precision
three-mask process of the proposed integration technology. The system components, i.e.,
filters, matching circuits, transitions, and combiners, are designed using the proposed allsilicon
technology and are hybrid integrated with the active chips to build the operational
THz system. The excitation method uses contactless silicon probes made in-lab for onwafer
probing of the devices. A novel self-contained THz probe is effectively designed and
fabricated to overcome assembly challenges at high frequencies. Two different THz probe
designs are used to characterize the source prototypes at D-band and Y-band. Based on
the simulations and measured data, the passive components exhibited high performance
with the proposed integration technology and were effectively employed to build the prototype
of the THz source. Upon excitation with a V-band input signal at the first stage, the
generated power at D-band reached −1 dBm. Consequently, novel designs incorporating
two combined signal branches were fabricated to adequately drive the second tripler stage
with sufficient input power, resulting in an approximate Y-band power level of −18 dBm
at a frequency of 0.5 THz.
Description
Keywords
terahertz silicon GaAs hybrid integration packaging tripler y-band d-band