Online Archive of University of Virginia Scholarship
Fabrication Advancements and Characterization of Heterogeneously Integrated Gallium Arsenide Schottky Diodes and Circuits140 views
Author
Moore, Christopher, Electrical Engineering - School of Engineering and Applied Science, University of Virginia
Advisors
Weikle, Robert, EN-Elec & Comp Engr Dept, University of Virginia
Abstract
This thesis presents an optimized fabrication process for heterogeneously integrated quasi-vertical gallium arsenide (GaAs) Schottky diodes (QVDs), building on prior work in our research group utilizing silicon micromachining. The process is tailored for compact membrane-based circuits, featuring closely spaced diodes with gold-plated, side-coated vias and freestanding 3-µm thick gold beam leads. The process has been optimized for <2 µm feature tolerance, minimizing or eliminating unwanted etch effects, such as undercutting, residue, and reduced processing time. One of these new approaches includes diffusion bonding, which achieves a metal-to-metal interface and enables integration onto silicon for enhanced thermal handling. The diffusion-bonded QVDs exhibit comparable electrical performance and superior thermal dissipation compared to previously fabricated adhesive-bonded diodes. Collaborative work with Virginia Diodes yielded membrane-based multiplier chip designs, where frequency doublers fabricated using the above-mentioned QVD process advancements were tested against lateral (planar) diode designs. The QVD offers potential advantages over the lateral/planar diode due to its geometry, including reduced parasitics, lower series resistance, and improved thermal handling.
Moore, Christopher. Fabrication Advancements and Characterization of Heterogeneously Integrated Gallium Arsenide Schottky Diodes and Circuits. University of Virginia, Electrical Engineering - School of Engineering and Applied Science, PHD (Doctor of Philosophy), 2024-12-08, https://doi.org/10.18130/x1k5-8r18.
