Array of Graphene Variable Capacitors on 100 mm Silicon Wafers for Vibration-Based Applications Article Swipe

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Wafer Graphene Materials science Capacitor Variable capacitor Optoelectronics Lithography Silicon Capacitance Nanotechnology Electrical engineering Voltage Electrode Engineering Physics Quantum mechanics

Millicent Gikunda , Ferdinand Harerimana , James M. Mangum , Sumaya Rahman , J. Thompson , Charles Thomas Harris , Hugh Churchill , P. M. Thibado ·

YOU? · · 2022 · Open Access · · DOI: https://doi.org/10.3390/membranes12050533 · OA: W4280518053

Highly flexible, electrically conductive freestanding graphene membranes hold great promise for vibration-based applications. This study focuses on their integration into mainstream semiconductor manufacturing methods. We designed a two-mask lithography process that creates an array of freestanding graphene-based variable capacitors on 100 mm silicon wafers. The first mask forms long trenches terminated by square wells featuring cone-shaped tips at their centers. The second mask fabricates metal traces from each tip to its contact pad along the trench and a second contact pad opposite the square well. A graphene membrane is then suspended over the square well to form a variable capacitor. The same capacitor structures were also built on 5 mm by 5 mm bare dies containing an integrated circuit underneath. We used atomic force microscopy, optical microscopy, and capacitance measurements in time to characterize the samples.