A Sensitivity-Enhanced Vertical-Resonant MEMS Electric Field Sensor Based on TGV Technology
Yahao Gao, Simin Peng, Xiangming Liu, Yufei Liu, Wei Zhang, Chunrong Peng, Shanhong Xia
Abstract
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%.