In order to enhance the sensitivity of wafer-level vacuum-packaged electric field sensors, this paper proposed a vertical-resonant MEMS electric field sensor based on TGV (Through Glass Via) technology. The microsensor is composed of the electric field sensing cover, the drive cover, and the SOI-based microstructures between them. TGV technology is innovatively used to fabricate the electric field sensing cover and the vertically-driven cover. The external electric field is concentrated and transmitted to the area below the silicon plate in the center of the electric field sensing cover through a metal plate and a metal pillar, reducing the coupling capacitance between the silicon plate and the packaging structure, thereby achieving the enhanced transmission of the electric field. The sensitivity-enhanced mechanism of the sensor is analyzed, and the key parameters of the sensor are optimized through finite element simulation. The fabrication process is designed and realized. A prototype is tested to characterize its performance. The experimental results indicate that the sensitivity of the sensor is 0.82 mV/(kV/m) within the electrostatic electric field ranging from 0–50 kV/m. The linearity of the sensor is 0.65%.

This paper proposes a highly sensitive and high-resolution resonant MEMS electrostatic field sensor based on electrostatic stiffness perturbation, which uses resonant frequency as an output signal to eliminate the feedthrough interference from the driving voltage. The sensor is composed of a resonator, driving electrode, detection electrode, transition electrode, and electrostatic field sensing plate. The working principle is that when there is an electrostatic field, an induction charge will appear at the surface of the electrostatic field sensing plate and induce electrostatic stiffness on the resonator, which will cause a resonant frequency shift. The resonant frequency is used as the output signal of the microsensor. The characteristics of the electrostatic field sensor are analyzed with a theoretical model and verified by finite element simulation. A device prototype is fabricated based on the Silicon on Insulator (SOI) process and tested under vacuum conditions. The results indicate that the sensitivity of the sensor is $0.1384\sqrt{\mathrm{Hz}}/\left(\mathrm{kV}/\mathrm{m}\right)$ and the resolution is better than 10 V/m.

This article presents a wafer-level vacuum-packaged vertical resonant electric field microsensor (EFM), which uses an anodic bonded glass in silicon, silicon on insulator, and glass on silicon (GIS–SOI–GOS) triple-stack structure. GIS is innovatively employed to fabricate the external driving electrode, which is used to vertically drive the resonator at the device layer of SOI. SOI is used to fabricate the sensing structure. GOS is used to establish the electric field induction channel. A theoretical model is established to characterize the output characteristics of the novel EFM. Numerical simulations are conducted to optimize the key structural parameters. The fabrication process based on bulk micromachining is employed to manufacture the microsensor. The developed EFM is characterized experimentally. The experimental results show that the air pressure in the vacuum chamber is about 5 Pa, and a driving voltage of 7 V dc and 0.07 V $_{\text{p}}$ ac is needed to realize the vertical resonance of the sensing structure. The microsensor demonstrates a sensitivity of 0.31 mV/(kV/m) with a linearity of 5.84% within the electric field range of 0–50 kV/m, which further improves the sensitivity of the wafer-level vacuum-packaged EFM.

This paper presents a novel high sensitivity mode-localization micro electric field sensor based on closed-loop feedback. The sensor is based on the principle that the mode localization effect can dramatically increase the sensitivity of a resonant system. Moreover, in order to detect the electric field in real time and improve the ability of the sensor, a closed-loop feedback is introduced. One of the output signals of the sensor is fed back to the input, where the output signal has been processed by phase-locked loop part and automatic gain control part. Tested in vacuum conditions, the minimum detectable DC electric field of the sensor is better than 10V/m, the accuracy of the sensor is 5.3%, and the repeatability is 0.56%.