Micromachined interferometric accelerometer fabricated using SGADER process

We presents a micromachined interferometric accelerometer fabricated using Silicon Glass Anodic-bonding and Deep Etching Release (SGADER) process. The accelerometer consists of a glass-silicon-glass sandwich structure. A proof mass is suspended by beams attached to the silicon support substrate and a diffraction grating on the bottom glass substrate resides under the proof mass. The sandwich structure and the protection stoppers on the proof mass can protect the support beams from damage induced by large acceleration. Illuminating the grating with collimated laser generates diffracted beams. The displacement between the proof mass and the grating is detected by measuring the intensity of the first order diffracted beam. The accelerometer was tested using a turntable. The acceleration resolution is better than 34µg, and the sensitivity is about 147 V/g.