CUED Publications database

A resonant micromachined electrostatic charge sensor

Zhu, Y and Lee, JEY and Seshia, AA (2008) A resonant micromachined electrostatic charge sensor. IEEE Sensors Journal, 8. pp. 1499-1505. ISSN 1530-437X

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A micromachined electrometer, based on the concept of a variable capacitor, has been designed, modeled, fabricated, and tested. The device presented in this paper functions as a modulated variable capacitor, wherein a dc charge to be measured is up-modulated and converted to an ac voltage output, thus improving the signal-to-noise ratio. The device was fabricated in a commercial standard SOI micromachining process without the need for any additional processing steps. The electrometer was tested in both air and vacuum at room temperature. In air, it has a charge-to-voltage conversion gain of 2.06 nV/e, and a measured charge noise floor of 52.4 e/rtHz. To reduce the effects of input leakage current, an electrically isolated capacitor has been introduced between the variable capacitor and input to sensor electronics. Methods to improve the sensitivity and resolution are suggested while the long-term stability of these sensors is modeled and discussed. © 2006 IEEE.

Item Type: Article
Uncontrolled Keywords: Electrostatic charge sensor Micromechanical resonator Transcapacitance amplifier (TCA) Variable capacitor Vibrating reed electrometer
Divisions: Div C > Applied Mechanics
Depositing User: Unnamed user with email
Date Deposited: 16 Jul 2015 13:12
Last Modified: 09 Oct 2015 23:28
DOI: 10.1109/JSEN.2008.923597