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- Creators: Computer Science and Engineering Program
Description
UniRate is a peer-driven digital review platform designed exclusively for college students to share honest, experience-based insights about all aspects of campus life, from housing and dining to academics and social culture. Unlike generalized platforms such as Yelp or Reddit, UniRate creates a trusted, student-verified ecosystem built “for students, by students,” promoting authenticity and relatability. UniRate is more than just a review site, it’s a cultural tool that modernizes how students choose, experience, and influence college life. UniRate aims to give information and access about universities never available before for the benefit of all who want to experience campus life.
ContributorsGaitan, Matthew (Author) / Hasson, Ethan (Co-author) / Wilhoit, Evan (Co-author) / Thorell, Jack (Co-author) / Burleson, Cole (Co-author) / Byrne, Jared (Thesis director) / Giles, Charles (Committee member) / Barrett, The Honors College (Contributor) / WPC Graduate Programs (Contributor) / Department of Finance (Contributor)
Created2025-05
Description
Conventional four-point-probe (4PP) stations achieve high-accuracy sheet-resistance measurements but often lack the ability to perform mapping across an area of a sample. Commercial tools also feature a large (80-100 mil) probe spacing, which limits the spatial resolution of the sheet-resistance measurement.We retrofitted an R-θ-Z wafer stage with a 3-D-printed probe head and spring-loaded, 410 µm-diameter gold pins, controlled through a new Python automation stack, to build a wafer-mapper. While the gold probe pins work well on metal films, sheet-resistance measurements on silicon samples require the probe tips to mechanically pierce the native SiO₂ that spontaneously grows on silicon wafers. For device-grade specimens this mechanical scratching is undesirable,because it could lead to the introduction of mechanical defects. Initial experiments were conducted that applied high-voltage (≤ 105V), low-current (≤ 1 mA) pulses to break down the oxide electrically. However, tip deformation increased the effective contact area, raising the breakdown voltage beyond practical limits and preventing reliable contact formation, causing large variations in the mapping data. We therefore explored a contact-less eddy-current approach using a single-loop RF coil. The RF excitation signal was swept from 100 kHz to 6 GHz while its complex reflection coefficient ( S₁₁ ) was captured. The resulting resonance-splitting or “fan-out” of S₁₁ spectra correlates monotonically with the sheet resistivity of test wafers (1-140 Ω □⁻¹). LTSpice models of the coil-wafer system reproduced the measured trends, lending confidence that calibrated peak-tracking can yield quantitative resistivity maps. This work demonstrates the feasibility of a hybrid probe station that performs non-contact characterization of bulk silicon samples. In future iterations this characterization technique can also be applied to thin-film measurements. Key design lessons and an outline for refining the probe head and extraction algorithms are presented.
ContributorsStringer, Evan (Author, Co-author) / Goryll, Michael (Thesis director) / Celano, Umberto (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor) / Computer Science and Engineering Program (Contributor)
Created2025-05