This paper presents a novel capacitive microelectromechanical systems (MEMS)\naccelerometer with slanted supporting beams and all-silicon sandwich structure. Its sensing\nmechanism is quite similar to an ordinary sandwich-type MEMS accelerometer, except that its\nproof mass is suspended by a beam parallel to the {111} plane of a (100) silicon wafer. In this way,\neach sensing element can detect accelerations in two orthogonal directions. Four of these sensing\nelements could work together and constitute a 3-axis micro-accelerometer by using a simple planar\nassembly process. This design avoids the traditional 3-axis accelerometerââ?¬â?¢ disadvantage of possible\nplacement inaccuracy when assembling on three different planes and largely reduces the package\nvolume. The slanted-beam accelerometerââ?¬â?¢s performance was modeled and analyzed by using both\nanalytical calculations and finite element method (FEM) simulations. A prototype of one sensing\nelement was fabricated and tested. Measured results show that this accelerometer has a good bias\nstability 76.8 ppm (1ÃÆ?, tested immediately after power on), two directional sensitivities (sensitivity\nangle Ã?± = 45.4ââ??¦) and low nonlinearity (<0.5%) over a sensing range up to Ã?±50 g, which demonstrates\na great opportunity for future high-precision three-axis inertial measurement.
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