A novel resonant silicon accelerometer in bulk-micromachining technology

✍ Scribed by Chr. Burrer; J. Esteve

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 431 KB
• Volume: 46
• Category: Article
• ISSN: 0924-4247
• DOI: 10.1016/0924-4247(94)00887-n

✦ Synopsis

The fabrication and characterization of a resonant accelerometer made in bulk-micromachining technology are reported. The device consists of a silicon seismic mass suspended by two hinges from one side. Between them, a load sensitive silicon beam is located, clamped to the bulk and to the mass. The beam is driven electrothermally and sensed piezoresistively. A double-diffusion electrochemical etch stop process was employed in order to fabricate a sensor structure, permitting elongation and compression of the beam under an out-of-plane load, with a single wafer bulk-micromachining fabrication process. Initial device measurements show a sensitivity of (200 \mathrm{~Hz} \mathrm{~g}{ }^{-1}) to out-of-plane accelerations at a beam oscillation frequency of 90 (\mathrm{kHz}). Operation of the sensor in a closed-loop circuit with an external automatic gain control circuit was successfully verified.