Title

Improved Sensitivity MEMS Cantilever Sensor for Terahertz Photoacoustic Spectroscopy

Document Type

Article

Language

eng

Publication Date

2-19-2016

Publisher

MDPI

Source Publication

Sensors

Source ISSN

1424-8220

Abstract

In this paper, a microelectromechanical system (MEMS) cantilever sensor was designed, modeled and fabricated to measure the terahertz (THz) radiation induced photoacoustic (PA) response of gases under low vacuum conditions. This work vastly improves cantilever sensitivity over previous efforts, by reducing internal beam stresses, minimizing out of plane beam curvature and optimizing beam damping. In addition, fabrication yield was improved by approximately 50% by filleting the cantilever’s anchor and free end to help reduce high stress areas that occurred during device fabrication and processing. All of the cantilever sensors were fabricated using silicon-on-insulator (SOI) wafers and tested in a custom built, low-volume, vacuum chamber. The resulting cantilever sensors exhibited improved signal to noise ratios, sensitivities and normalized noise equivalent absorption (NNEA) coefficients of approximately 4.28 × 10−10cm−1·WHz−1/2. This reported NNEA represents approximately a 70% improvement over previously fabricated and tested SOI cantilever sensors for THz PA spectroscopy

Comments

Sensors, Vol. 16, No. 2 (2016)L 251. DOI. © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Share

COinS