Optimized design and process for making a DC voltage reference based on MEMS
A micromechanical moving plate capacitor has been designed and fabricated for use as a dc voltage reference. The reference is based on the characteristic pull-in property of a capacitive microelectromechanical system (MEMS) component. The design is optimized for stability. A new silicon-on-insulator (SOI) process has been developed to manufacture the component. We also report on improved feedback electronics and the latest measurement results.
DC Voltage Reference Based on a Square-Wave-Actuated Microelectromechanical Sensor
Long-term stability of a dc voltage standard based on a capacitive microelectromechanical system (MEMS) is investigated. Square-wave voltage actuation was used to cancel the effect of slow charging appearing in the dielectric layers and capacitor plate surfaces of the MEMS capacitor. The key properties of a MEMS capacitor and the operational principle and the measurement results of the apparatus that implements the voltage standard are explained. Negligible voltage drift within the measurement scatter of ± 2 parts per million during a 22-day measurement period was demonstrated.
Linking electrical with mechanical quantities through electro-mechanical resonance
The possibility of an electro-mechanical harmonic oscillator obtained by coupling two linear capacitive voltage-force transducers with a common floating mass is shown. Approaching a constant-charge operation, the system yields a very-low-frequency ac voltage related to mass through capacitance, length and frequency. A possible use in the determination of the Josephson constant or the Planck constant is also outlined.