Assessment of dielectric charging in capacitive MEMS switches fabricated on Si substrate with thin oxide film

• Dielectric charging is assessed in MEMS switches with substrate interference.
• A new method is proposed to investigate dielectric charging.
• Assessment separates the contribution of the substrate network.
• The method has been applied to monitor the charging build-up during device stress.

The paper presents a new method to determine and monitor the surface charge density of dielectric film in capacitive MEMS switches which experience a significant interference from substrate parasitic MOS capacitors coupling. The method is based on the analysis of composite MEMS device and bridge-less back-to-back substrate MOS capacitors. The difference of the derivatives of the two device C-V characteristics allows the calculation of dielectric film charge density. The method has been applied to monitor the charging build-up during device stress.

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