| Autor: |
Riehl, Patrick S., Scott, Karen L., Muller, Richard S., Howe, Roger T., Yasaitis, John A. |
| Předmět: |
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| Zdroj: |
Journal of Microelectromechanical Systems; Oct2003, Vol. 12 Issue 5, p577-589, 13p, 6 Black and White Photographs, 12 Diagrams, 3 Charts, 11 Graphs |
| Abstrakt: |
We have developed highly sensitive electrometers and electrostatic fieldmeters (EFMs) that make use of micromechanical variable capacitors. Modulation of the input capacitance, a technique used in macroscale instruments such as the vibrating-reed electrometer and the field-mill electrostatic voltmeter (ESV), moves the detection bandwidth away from the 1/f-noise-limited regime, thus improving the signal-to-noise ratio (SNR). The variable capacitors are implemented by electrostatically driven resonators with differential actuation and sensing to reduce drive-signal feedthrough. The resonators in the electrometer utilize a balanced comb structure to implement harmonic sensing. Two fabrication methods were employed-a hybrid technology utilizing fluidically self-assembled JFETs and SOl microstructures, and an integrated process from Analog Devices combining 0.8-µm CMOS and 6-µm-thick polysilicon microstructures. All devices operate in ambient air at room temperature. Measured data from one electrometer with an input capacitance of 0.7 pF indicates a charge resolution of 4.5 aC rms (28 electrons) in a 0.3 Hz bandwidth. The resolution of this electrometer is unequaled by any known ambient-air-operated instrument over a wide range of source capacitances. The EFM has a resolution of 630 V/m, the best reported figure for a MEMS device. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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