Glass Polarization Induced Drift of a Closed-Loop Micro-Accelerometer
School of Mechanical and Electrical Engineering, University of Electronic Technology and Science of China, Chengdu 611731, China
School of Mechanical Engineering, Xihua University, Chengdu 610039, China
Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, China
Authors to whom correspondence should be addressed.
Materials 2018, 11(1), 163; https://doi.org/10.3390/ma11010163
Received: 8 December 2017 / Revised: 15 January 2018 / Accepted: 19 January 2018 / Published: 20 January 2018
The glass polarization effects were introduced in this paper to study the main cause of turn-on drift phenomenon of closed-loop micro-accelerometers. The glass substrate underneath the sensitive silicon structure underwent a polarizing process when the DC bias voltage was applied. The slow polarizing process induced an additional electrostatic field to continually drag the movable mass block from one position to another so that the sensing capacitance was changed, which led to an output drift of micro-accelerometers. This drift was indirectly tested by experiments and could be sharply reduced by a shielding layer deposited on the glass substrate because the extra electrical filed was prohibited from generating extra electrostatic forces on the movable fingers of the mass block. The experimental results indicate the average magnitude of drift decreased about 73%, from 3.69 to 0.99 mV. The conclusions proposed in this paper showed a meaningful guideline to improve the stability of micro-devices based on silicon-on-glass structures.