An All-Silicon Comb-Tooth Capacitive MEMS Accelerometer

Abstract

An all-silicon comb tooth capacitive MEMS accelerometer with navigation potential is designed, fabricated and tested. Eight sets of variable-gap differential combs, four U-shaped springs and one frame-type sensitive mass constitute the sensitive structure of the accelerometer, which is fabricated by deep reactive ion etching (DRIE), and encapsulated by silicon–silicon fusion bonding at wafer level at normal pressure. Internal signals of the accelerometer are led out through through silicon vias (TSV) that fabricated by DRIE and wet etching. An analog application specific integrated circuit (ASIC) with double-terminal charge amplification interface and parameterizable PID is used to adapt the accelerometer. The MEMS chip and the ASIC chip are packaged in a ceramic shell finally. Test results show that the scale factor of the accelerometer is about 0.104 V/g, the bias stability and repeatability are better than 50 μg(1σ), the stability and repeatability of the scale factor are better than 40 ppm(1σ); the bias drift is about 3 mg and the scale factor change is about 2500 ppm between −40 and 60 ℃, and the vibration rectification error (VRE) is less than 40 μg/g².