Design and Fabrication of a Microelectromechanical Double-Ended Tuning Fork Strain Gauge
Abstract
A double-ended tuning fork (DETF) strain gauge that can be used for strain and force measurements is designed and fabricated in this work. The design of the sensor was augmented by an analytical model using the linear beam theory, by numerical simulations performed in COMSOL Multiphysics 5.2 and by an electromechanical state-space model simulated in Matlab. The predicted sensitivity of the gauge was 57.7 Hz/μϵ for the analytical formulation and 49.8 Hz/μϵ for the FEM model. The fabrication of the device was performed at the Birck Nanotechnology Center cleanroom using UV photolithography for metal pad and device layer definition, followed by an electron beam evaporation of chromium and gold for the contacts and a DRIE process for etching the silicon layer of the SOI wafer. The devices where released using a vapor HF system which was a high-yield process. The device was tested, however due to the under etching of silicon parts of the comb drive were connecting together which allowed no possible motion of the structure.
Degree
M.S.
Advisors
Leon-Salas, Purdue University.
Subject Area
Engineering
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