Sensitivity Jump of Micro Accelerometer Induced by Micro-fabrication Defects of Micro Folded Beams

Abstract

The abnormal phenomenon occurring in sensor calibration is an obstacle to product development but a useful guideline to product improvement. The sensitivity jump of micro accelerometers in the calibrating process is recognized as an important abnormal behavior and investigated in this paper. The characteristics of jumping output in the centrifuge test are theoretically and experimentally analyzed and their underlying mechanism is found to be related to the varied stiffness of supporting beam induced by the convex defect on it. The convex defect is normally formed by the lithography deviation and/or etching error and can result in a jumping stiffness of folded microbeams and further influence the sensitivity when a part of the bending beams is stopped from moving by two surfaces contacting. The jumping level depends on the location of convex and has nothing to do with the contacting properties of beam and defects. Then the location of defect is predicted by theoretical model and simulation and verified by the observation of micro structures under microscopy.The results indicate that the tested micro accelerometer has its defect on the beam with a distance of about 290μm from the border of proof mass block.

Material Viscoelasticity-Induced Drift of Micro-Accelerometers

“…The whole structure is packaged onto a ceramic shell with an epoxy-based adhesive through a curing process. When an acceleration, a , is applied in the sensitive direction, the movement of the proof mass induced by inertial force generates a gap change of sensing capacitors formed by a fixed finger on the silicon substrate and a movable finger on the proof mass [ 19 , 20 ]. The changed gap shifts the differential capacitance of capacitors, C 1 and C 2 , and the output of the micro-accelerometer can be simply expressed as: where V out is the output voltage of accelerometer, G is the amplification coefficient of the sensing circuit and V b is the amptitude of carrier voltage.…”

Research on Novel Denoising Method of Variational Mode Decomposition in MEMS Gyroscope

“…The MEMS gyroscope has advantages in small size, light weight, low cost, low power consumption and high reliability, and is suitable for small navigation systems [1]- [9] . With the development of modern science and technology and needs, the accuracy of MEMS gyroscope measurement requirements is getting higher and higher [10], [11].…”

Effects of thermal loading on the deployment of four-bar linkages for retractable roof structures

“…Deployable structure, which is a structure that can change its size by changing its shape, is widely used in daily life such as tents and umbrellas. Current interest in deployable structures arises mainly from their potential in space engineering, civil engineering and MEMS [1][2][3].The deployment analysis is an important part in the theoretical research and design of deployable structures.…”